Transition metal sulfides have high theoretical capacities and are considered as potential anode materials for sodium-ion batteries.However,due to low inherent conductivity and significant volume expansion,the electro...Transition metal sulfides have high theoretical capacities and are considered as potential anode materials for sodium-ion batteries.However,due to low inherent conductivity and significant volume expansion,the electrochemical performance is greatly limited.In this study,a nickel/manganese sulfide material(Ni_(0.96)S_(x)/MnS_(y)-NC)with adjustable sulfur vacancies and heterogeneous hollow spheres was prepared using a simple method.The introduction of a concentration-adjustable sulfur vacancy enables the generation of a heterogeneous interface between bimetallic sulfide and sulfur vacancies.This interface collectively creates an internal electric field,improving the mobility of electrons and ions,increasing the number of electrochemically active sites,and further optimizing the performance of Na~+storage.The direction of electron flow is confirmed by Density functional theory(DFT)calculations.The hollow nano-spherical material provides a buffer for expansion,facilitating rapid transfer kinetics.Our innovative discovery involves the interaction between the ether-based electrolyte and copper foil,leading to the formation of Cu_9S_5,which grafts the active material and copper current collector,reinforcing mechanical supporting.This results in a new heterostructure of Cu_9S_5 with Ni_(0.96)S_(x)/MnS_(y),contributing to the stabilization of structural integrity for long-cycle performance.Therefore,Ni_(0.96)S_(x)/MnS_(y)-NC exhibits excellent electrochemical properties following our modification route.Regarding stability performance,Ni0_(.96)S_(x)/MnS_(y)-NC demonstrates an average decay rate of 0.00944%after 10,000 cycles at an extremely high current density of 10000 mA g^(-1),A full cell with a high capacity of 304.2 mA h g^(-1)was also successfully assembled by using Na_(3)V_(2)(PO_(4))_(3)/C as the cathode.This study explores a novel strategy for interface/vacancy co-modification in the fabrication of high-performance sodium-ion batteries electrode.展开更多
Selective CO_(2)-to-CO photoreduction is under intensive research and requires photocatalysts with tuned microstructures to accelerate the reaction kinetics.Here,we report CuInS_(2)nanosheet arrays with sulfur vacanci...Selective CO_(2)-to-CO photoreduction is under intensive research and requires photocatalysts with tuned microstructures to accelerate the reaction kinetics.Here,we report CuInS_(2)nanosheet arrays with sulfur vacancies(VS)grown on the two-dimensional(2D)support of Ti_(3)C_(2)T_(x)MXene for CO_(2)-to-CO photoreduction.Our results reveal that the use of Ti_(3)C_(2)T_(x)induces strong support effect,which causes the hierarchical nanosheet arrays growth of CuInS_(2)and simultaneously leads to charge transfer from CuInS_(2)to Ti_(3)C_(2)T_(x)support,resulting in VSformed in CuInS_(2).The strong support effect based on Ti_(3)C_(2)T_(x)is proven to be applicable to prepare a series of different metal indium sulfide arrays with VS.CuInS_(2)nanosheet arrays with VSsupported on Ti_(3)C_(2)T_(x)benefit the photocatalytic selective reduction of CO_(2)to CO,manifesting a remarkable over 14.8-fold activity enhancement compared with pure CuInS_(2).The experimental and computational investigations pinpoint that VSof CuInS_(2)resulting from the support effect of Ti_(3)C_(2)T_(x)lowers the barrier of the rate-limiting step of^(*)COOH→^(*)OH+^(*)CO,which is the key to the photoactivity enhancement.This work demonstrates MXene support effects and offers an effective approach to regulate the atomic microstructure of metal sulfides toward enhancing photocatalytic performance.展开更多
Nowadays,it is a matter of great concern to design electrode materials with excellent electrochemical performance for supercapacitors by a safe,efficient and simple method.And these characteristics are usually related...Nowadays,it is a matter of great concern to design electrode materials with excellent electrochemical performance for supercapacitors by a safe,efficient and simple method.And these characteristics are usually related to the vacancies and impurities in the electrode.To investigate the effect of the vacancies on the electrochemical properties of the supercapacitor cathode material,the uniform reduced CoNi2S4(r-CoNi2S4)nanosheets with sulfur vacancies have been successfully prepared by a one-step hydrothermal method.And the formation of sulfur vacancies are characterized by Raman,X-ray photoelectron spectroscopy and other means.As the electrode for supercapacitor,the r-CoNi2S4 nanosheet electrode delivers a high capacity of 1918.9 Fg-1 at a current density of 1 A g-1,superior rate capability(87.9%retention at a current density of 20 A g-1)and extraordinary cycling stability.Compared with the original CoNi2S4 nanosheet electrode(1226 F g-1at current density of 1 A g-1),the r-CoNi2S4 nanosheet electrode shows a great improvement.The asymmetric supercapacitor based on the r-CoNi2S4 positive electrode and activated carbon negative electrode exhibits a high energy density of 30.3 Wh kg-1 at a power density of 802.1 W kg-1,as well as excellent long-term cycling stability.The feasibility and great potential of the device in practical applications have been successfully proved by lightening the light emitting diodes of three different colors.展开更多
Integrating the advantages of anion vacancies and heterostructures into the catalytic materials may increase the binding affinities to intermediates, provide more active sites, and significantly promote the activity o...Integrating the advantages of anion vacancies and heterostructures into the catalytic materials may increase the binding affinities to intermediates, provide more active sites, and significantly promote the activity of overall water splitting. However, the successful assembly of anion vacancies and heterostructures for high-efficiency water splitting performance is still challenging. In this work, we ingeniously present the co-construction of sulfur vacancies and heterogeneous interface into Ni_(3)S_(2)/MoS_(2) catalysts on nickel foam(NF). The introduction of sulfur vacancies and Ni_(3)S_(2)/MoS_(2) heterostructures can significantly improve electron and ion transport, effectively improve structural stability, and enhance overall water splitting activity. The obtained VSNi_(3)S_(2)/MoS_(2) catalysts(VS stands for sulfur vacancies) exhibit superior OER and HER activities,and the overpotentials for OER and HER are 180 and 71 mV at 10 mA·cm^(-2), respectively. Furthermore, a low water splitting voltage of 1.46 V is required at 10 mA·cm^(-2) for the VS-Ni_(3)S_(2)/MoS_(2) catalysts, which is considerably lower than most that of water splitting electrocatalysts currently reported. This work offers an effective mean for the preparation of catalysts with both anion vacancies and heterostructures for achieving high-performance alkaline overall water splitting.展开更多
To suppress the inner charge recombination and inject vast electrons,CdTe nanocrystals are embedded into ultrathin ZnIn_(2)S_(4) nanosheets to construct ZnIn_(2)S_(4)/CdTe heterostructures,where the nanocrystals are g...To suppress the inner charge recombination and inject vast electrons,CdTe nanocrystals are embedded into ultrathin ZnIn_(2)S_(4) nanosheets to construct ZnIn_(2)S_(4)/CdTe heterostructures,where the nanocrystals are generated by a laser irradiation method.The optimal ZnIn_(2)S_(4)/CdTe heterojunction exhibits an excellent catalytic activity of 24.3 mmol/h/g,which is relatively high among the ZnIn_(2)S_(4)-based photocatalysts with-out noble metals.This enhancement is ascribed to a win-win mechanism of nanoscale heterojunctions and sulfur vacancies.The strong electron coupling effect,which is verified by density functional the-ory(DFT)calculations,impels the photo-generated electrons transfer from CdTe to ZnIn_(2)S_(4),boosting the charge separation.Meanwhile,the sulfur vacancies existing in ZnIn_(2)S_(4) can capture photoelectrons and act as active sites,facilitating the H_(2) generation reaction.In addition,the ZnIn_(2)S_(4) base and the ZnIn_(2)S_(4)/CdTe heterojunction also possess an evident photothermal effect and renewable cycle phenomena,enhancing the photocatalytic performance.This research provides new insights into the regulation of charge transfer through embedding nanocrystals.展开更多
Yarn-based batteries with the dual functions of wearable and energy storage have demonstrated promising potential in wearable energy textiles.However,it is still an urgent problem to construct efficient and flexible e...Yarn-based batteries with the dual functions of wearable and energy storage have demonstrated promising potential in wearable energy textiles.However,it is still an urgent problem to construct efficient and flexible electrodes while optimize the configuration of yarn-based batteries to maintain excellent electrochemical performance under different mechanical deformations.Herein,NiCo_(2)S_(4-x) nanotube arrays with tunable S-vacancies are constructed on carbon yarn(CY)(NiCo_(2)S_(4-x)@CY)by a facile hydrothermal strategy.The aqueous zinc-ion batteries(ZIBs)with NiCo_(2)S_(4-x)@CY as cathodes exhibit exceptional discharge capacity(271.7 mAh g^(-1))and outstanding rate performance(70.9%capacity retention at 5 A g^(-1)),and reveal a maximum power density of 6,059.5 W kg^(-1) and a maximum energy density of 432.2 Wh kg^(-1).It is worth noting that the tunable S-vacancies promote the surface reconfiguration and phase transitions of NiCo_(2)S_(4-x),thereby enhancing the conductivity and charge storage kinetics.The high reactivity and cycling stability of NiCo_(2)S_(4-x)@CY can be related to the discharge products of S-doped NiO and CoO.Furthermore,flexible stretchable yarn-based ZIBs with wrapped yarn structures are constructed and exhibit excellent tensile stability and durability under a variety of mechanical deformations.As a proof of concept,the ZIBs integrated into the fabric show excellent electrochemical performance even in response to simultaneous stretching and bending mechanical deformations.The proposed strategy provides novel inspiration for the development of highly efficient and economical yarn-based ZIBs and wearable energy textiles.展开更多
Due to the relatively sluggish charge carrier separation in metal sulfides,the photocatalytic activity of them is still far lower than expected.Herein,sulfur vacancies and in-plane SnS_(2)/SnO_(2) heterojunction were ...Due to the relatively sluggish charge carrier separation in metal sulfides,the photocatalytic activity of them is still far lower than expected.Herein,sulfur vacancies and in-plane SnS_(2)/SnO_(2) heterojunction were successfully introduced into the SnS_(2) nanosheets through high energy ball-milling.These defective structures were studied by the electron paramagnetic resonance,Raman spectra,X-ray photoelectron spectroscopy,and high-resolution transmission electron microscope analyses.The sulfur vacancies and in-plane heterojunctions strongly accelerate the separation of photoexcited electron-hole pairs,as confirmed by the photo luminesce nce emission spectra and time-resolved photoluminescence decay spectra.The introduction of sulfur vacancies and in-plane heterojunction in SnS_(2) nanosheets results in roughly six times higher photodegrading rate for methyl orange and four times higher photocatalytic reduction rate of Cr6+than those of pure SnS_(2) nanosheets.展开更多
Peroxymonosulfate(PMS)activation in heterogeneous processes is a promising water treatment technology.Nevertheless,the high energy consumption and low efficiency during the reaction are ineluctable,due to electron cyc...Peroxymonosulfate(PMS)activation in heterogeneous processes is a promising water treatment technology.Nevertheless,the high energy consumption and low efficiency during the reaction are ineluctable,due to electron cycling rate limitation.Herein,a new strategy is proposed based on a quantum dots(QDs)/PMS system.Co-ZnS QDs are synthesized by a water phase coprecipitation method.The inequivalent lattice-doping of Co for Zn leads to the generation of surface sulfur vacancies(SVs),which modulates the surface of the catalyst to form an electronic nonequilibrium surface.Astonishingly,the plasticizer micropollutants can be completely degraded within only tens of seconds in the Co-Zn S QDs/PMS system due to this type of surface modulation.The interfacial reaction mechanism is revealed that pollutants tend to be adsorbed on the cobalt metal sites as the electron donors,where the internal electrons of pollutants are captured by the metal species and transferred to the surface SVs.Meanwhile,PMS adsorbed on the SVs is reduced to radicals by capturing electrons,achieving effective electron recovery.Dissolved oxygen(DO)molecules are also easily attracted to catalyst defects and are reduced to O_(2)^(·-),further promoting the degradation of pollutants.展开更多
Transition metal sulfides are demonstrated to play an increasingly important role in boosting the deployment of ecofriendly electrocatalytic energy conversion technologies.It is also widely recognized that the introdu...Transition metal sulfides are demonstrated to play an increasingly important role in boosting the deployment of ecofriendly electrocatalytic energy conversion technologies.It is also widely recognized that the introduction of vacancies is now becoming an important and valid approach to promote the electrocatalytic performance.In this review,the significance of sulfur vacancies on the enhancement of catalytic performance via four main functionalities,including tuning the electronic structure,tailoring the active sites,improving the electrical conductivity,and regulating surface reconstruction,is comprehensively summarized.Many effective strategies for the sulfur vacancy engineering,such as plasma treatment,heteroatom doping,and chemical reduction are also comprehensively provided.Subsequently,recent achievements in sulfur vacancy fabrication on various hotspot electrocatalytic reactions are also systematically discussed.Finally,a summary of the recent progress and challenges of this interesting field are organized,which hopes to guide the future development of more efficient metal sulfide electrocatalysts.展开更多
Magnetron-sputtered MoS_(2) has applications in piezoresistive functional materials research owing to its unique nanostructure.However,the controlled incorporation of sulfur vacancies and realization of en-hanced piez...Magnetron-sputtered MoS_(2) has applications in piezoresistive functional materials research owing to its unique nanostructure.However,the controlled incorporation of sulfur vacancies and realization of en-hanced piezoresistive performance remain significant challenges.In this work,the direct growth of large-area MoS_(2) films with tunable sulfur vacancy concentrations was successfully achieved via magnetron sputtering at various temperatures.Microstructural analysis revealed that the application of strain al-tered the number of conductive channels between the vertical MoS_(2) nanosheets,changing the measured resistance and leading to excellent piezoresistive properties.More importantly,the unsaturated electrons due to the sulfur vacancies increased the in-plane carrier concentration of the MoS_(2)nanosheets.A de-position temperature of 50℃afforded the highest concentrations of sulfur vacancies and carriers.These MoS_(2)films possessed a carrier concentration of 6.58×10^(17)cm^(−3),which was 40.9%higher than that ob-tained at 150°C,and displayed superior piezoresistive performance.The films exhibited high gage factors of 2.66 and 23.22 under tensile and compressive strain of≤0.29%,respectively.These values were 118%and 323%higher,respectively,than those obtained for films deposited at 150°C.This work provides an effective route for modulating and mass producing MoS_(2)-based piezoresistive electronic devices.展开更多
Structure manipulation of photocatalysts at an atomic scale is a promising way to improve its photocatalytic performance.Herein,we realize the anchoring of single Ni atoms on the ZnIn_(2)S_(4) nanosheets with rich sul...Structure manipulation of photocatalysts at an atomic scale is a promising way to improve its photocatalytic performance.Herein,we realize the anchoring of single Ni atoms on the ZnIn_(2)S_(4) nanosheets with rich sulfur vacancies.Experimental results demonstrate that single Ni atoms induce the formation of NiO-M(Zn/In) atomic interface,which can efficiently promote the carriers separation and prolong the carrier life time.In addition,in situ electron spin resonance spectroscopy(ESR) confirms that the single Ni atoms act as an electron trapping center for protons reduction.As a result,the single Ni atoms decorated ZnIn_(2)S_(4) nanosheets with rich sulfur vacancies(Ni/ZnIn_(2)S_(4)-RVs) shows a hydrogen evolution rate up to 89.4 μmol h^(-1), almost 5.7 and 2.3 times higher compared to that of ZnIn_(2)S_(4) nanosheets with poor sulfur vacancies and rich sulfur vacancies(denoted as ZnIn_(2)S_(4)-PVs and ZnIn_(2)S_(4)-RVs).This work opens up a new perspective manipulating the single-atom cocatalyst and sulfur vacancy on sulfide supports for improving photocatalytic hydrogen evolution.展开更多
Rational design and construction of highly efficient nonprecious electrocatalysts for oxygen reduction and alcohols oxidation reactions(ORR,AOR)are extremely vital for the development of direct oxidation alkaline fuel...Rational design and construction of highly efficient nonprecious electrocatalysts for oxygen reduction and alcohols oxidation reactions(ORR,AOR)are extremely vital for the development of direct oxidation alkaline fuel cells,metal-air batteries,and water electrolysis system involving hydrogen and value-added organic products generation,but they remain a great challenge.Herein,a bifunctional electrocatalyst is prepared by anchoring CuS/NiS_(2)nanoparticles with abundant heterointerfaces and sulfur vacancies on graphene(Cu_(1)Ni_(2)-S/G)for ORR and AOR.Benefiting from the synergistic effects between strong interfacial coupling and regulation of the sulfur vacancies,Cu_(1)Ni_(2)-S/G achieves dramatically enhanced ORR activity with long term stability.Meanwhile,when ethanol is utilized as an oxidant for AOR,an ultralow potential(1.37 V)at a current density of 10 mA cm-2 is achieved,simultaneously delivering a high Faradaic efficiency of 96%for ethyl acetate production.Cu_(1)Ni_(2)-S/G also exhibits catalytic activity for other alcohols electrooxidation process,indicating its multifunctionality.This work not only highlights a viable strategy for tailoring catalytic activity through the synergetic combination of interfacial and vacancies engineering,but also opens up new avenues for the construction of a self-driven biomass electrocatalysis system for the generation of value-added organic products and hydrogen under ambient conditions.展开更多
Hydrogen generation and related energy applications heavily rely on the hydrogen evolution reaction(HER),which faces challenges of slow kinetics and high overpotential.Efficient electrocatalysts,particularly single-at...Hydrogen generation and related energy applications heavily rely on the hydrogen evolution reaction(HER),which faces challenges of slow kinetics and high overpotential.Efficient electrocatalysts,particularly single-atom catalysts (SACs) on two-dimensional (2D) materials,are essential.This study presents a few-shot machine learning (ML) assisted high-throughput screening of 2D septuple-atomic-layer Ga_(2)CoS_(4-x)supported SACs to predict HER catalytic activity.Initially,density functional theory (DFT)calculations showed that 2D Ga_(2)CoS4is inactive for HER.However,defective Ga_(2)CoS_(4-x)(x=0–0.25)monolayers exhibit excellent HER activity due to surface sulfur vacancies (SVs),with predicted overpotentials (0–60 mV) comparable to or lower than commercial Pt/C,which typically exhibits an overpotential of around 50 m V in the acidic electrolyte,when the concentration of surface SV is lower than 8.3%.SVs generate spin-polarized states near the Fermi level,making them effective HER sites.We demonstrate ML-accelerated HER overpotential predictions for all transition metal SACs on 2D Ga_(2)CoS_(4-x).Using DFT data from 18 SACs,an ML model with high prediction accuracy and reduced computation time was developed.An intrinsic descriptor linking SAC atomic properties to HER overpotential was identified.This study thus provides a framework for screening SACs on 2D materials,enhancing catalyst design.展开更多
First-principles calculations based on density functional theory (DFT) and the generalized gradient approximation (GGA) have been used to study the adsorption of CO molecule on the perfect and defective FeS 2 (10...First-principles calculations based on density functional theory (DFT) and the generalized gradient approximation (GGA) have been used to study the adsorption of CO molecule on the perfect and defective FeS 2 (100) surfaces. The defective Fe 2 S(100) surfaces are caused by sulfur deficiencies. Slab geometry and periodic boundary conditions are employed with partial relaxations of atom positions in calculations. Two molecular orientations, Cand O-down, at various distinct sites have been considered. Total energy calculations indicated that no matter on perfect or deficient surfaces, the Fe position is relatively more favored than the S site with the predicted binding energies of 120.8 kJ/mol and 140.8 kJ/mol, respectively. Moreover, CO was found to be bound to Fe atom in vertical configuration. The analysis of density of states and vibrational frequencies before and after adsorption showed clear changes of the C–O bond.展开更多
A facile method of combining the defect engineering with the dielectric-screening effect is proposed to improve the electrical performance of MoS_(2) transistors. It is found that the carrier mobility of the transisto...A facile method of combining the defect engineering with the dielectric-screening effect is proposed to improve the electrical performance of MoS_(2) transistors. It is found that the carrier mobility of the transistor after the sulfur treatment on the MoS_(2) channel is greatly enhanced due to the reduction of the sulfur vacancies during vulcanization of MoS_(2).Furthermore, as compared to those transistors with HfO2 and SiO2 as the gate dielectric, the Al2O3-gate dielectric MoS_(2) FET shows a better electrical performance after the sulfur treatment, with a lowered subthreshold swing of 179.4 m V/dec,an increased on/off ratio of 2.11 × 10^(6), and an enhanced carrier mobility of 64.74 cm^(2)/V·s(about twice increase relative to the non-treated MoS_(2) transistor with SiO2 as the gate dielectric). These are mainly attributed to the fact that a suitable k-value gate dielectric can produce a dominant dielectric-screening effect overwhelming the phonon scattering, increasing the carrier mobility, while a larger k-value gate dielectric will enhance the phonon scattering to counteract the dielectricscreening effect, reducing the carrier mobility.展开更多
Developing a selective hydrogenation strategy over a low-cost electrocatalyst,especially with an inexpensive and safe hydrogen source for efficient synthesis of aminoareneswith fragile functional groups,is extremely d...Developing a selective hydrogenation strategy over a low-cost electrocatalyst,especially with an inexpensive and safe hydrogen source for efficient synthesis of aminoareneswith fragile functional groups,is extremely desirable.Herein,using H_(2)O as the hydrogen source,Ti mesh-supported Co_(3)S_(4)ultrathin nanosheets with sulfur vacancies(denoted as Co_(3)S_(4−x)NS)have been demonstrated to be a highly efficient cathode for selective transfer hydrogenation of nitroarenes to corresponding aminoarenes at low potential.D_(2)O-labeling experiments confirmed the hydrogen origin.Without sulfur vacancies,the products were a mixture of aminoarenes and azoxyareneswith lowselectivity.This method can deliver a variety of aminoarenes with outstanding selectivity and excellent functional group compatibility with highly reducible groups(e.g.,C–I,C–Br,C=O,C=C,C=N,C≡N,and C≡C).The experimental and theoretical results have revealed that sulfur vacancies can enhance the selective specific adsorption of the nitro group and promote intrinsic activity to form active hydrogen from water electrolysis,thus resulting in high selectivity and outstanding fragile functional groups tolerance.展开更多
Zeolite Imidazole Framework(ZIF)has the advantages of large specific surface area,high porosity,and easy functionalization,so it looked like one of the most promising energy storage and conversion materials.In the mea...Zeolite Imidazole Framework(ZIF)has the advantages of large specific surface area,high porosity,and easy functionalization,so it looked like one of the most promising energy storage and conversion materials.In the meantime,transition metal oxides and sulfides have been widely used in environmental and energy conversion applications.Hence,a NaOH-assisted thioacetamide etching strategy is,therefore,designed with the metal-organic framework as precursor to realize the hollow nanostructure of ZIF bimetallic sulfide(Sx-CoCd-350)with abundant sulfur vacancies for enhanced catalysts oxygen evolution reaction(OER)/hydrogen evolution reaction(HER)performance and capacitance performance of capacitor.The overpotential of S_(2)-CoCd-350 in the OER process is 355 m V at 50 m A cm^(-2),which is substantially lower than other reported ZIF-based catalysts.S_(2)-CoCd-350 has an overpotential of 84 m V at 10 m A cm^(-2)when employed as HER catalyst.Furthermore,the S_(2)-CoCd-350 electrode did not alter appreciably during a long-term durability test of more than 10 h.More impressively,S_(2)-Co Cd-350 matches the activated carbon(AC)electrode with excellent capacitance performance 1220μWh cm^(-2)energy density(at 3370μW cm^(-2))and 25,000μW cm^(-2)(at 700μWh cm^(-2))maximum power density.In addition,the assembled supercapacitor has excellent cycling stability.展开更多
MoS_(2)is a promising electrocatalyst because of its natural abundance and outstanding electrochemical stability.However,the poor conductivity and low activity limit its catalytic performance;furthermore,MoS_(2)is una...MoS_(2)is a promising electrocatalyst because of its natural abundance and outstanding electrochemical stability.However,the poor conductivity and low activity limit its catalytic performance;furthermore,MoS_(2)is unable to satisfy the requirements of most industrial applications.In this study,to obtain a P-doped MoS_(2)catalyst with S vacancy defects,P is inserted into the MoS_(2)matrix via a solid phase ion exchange at room temperature.The optimal P-doping amount is 11.4 wt%,and the resultant catalyst delivers excellent electrocatalytic properties for the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)with the corresponding overpotentials of 93 and 316 mV at 10 mA cm^(-2) in an alkaline solution;these values surpass the overpotentials of most previously reported MoS_(2)-based materials.Theoretical calculations and results demonstrate that the synergistic effect of the doped P,which forms active centers in the basal plane of MoS_(2),and S vacancy defects caused by P doping intensifies the intrinsic electronic conductivity and electrocatalytic activity of the catalyst.Density functional theory calculations demonstrate that P optimizes the free energy of the MoS_(2)matrix for hydrogen adsorption,thereby considerably increasing the intrinsic activity of the doped catalyst for the HER compared with that observed from pristine MoS_(2).The enhanced catalytic activity of P-doped MoS_(2)for the OER is attributed to the ability of the doped P which facilitates the adsorption of hydroxyl and hydroperoxy intermediates and reduces the reaction energy barrier.This study provides a new environmentally friendly and convenient solid-phase ion exchange method to improve the electrocatalytic capability of two-dimensional transition-metal dichalcogenides in largescale applications.展开更多
Seeking catalysts with high electrocatalytic activity for ambient-condition N2 reduction reaction (NRR) remains an ongoing challenge due to the chemical inertness of N2.Herein,defect-rich WS2 nanosheets (WS2-x) were d...Seeking catalysts with high electrocatalytic activity for ambient-condition N2 reduction reaction (NRR) remains an ongoing challenge due to the chemical inertness of N2.Herein,defect-rich WS2 nanosheets (WS2-x) were designed as an efficient electrocatalyst for NRR,which were prepared via vulcanizing the oxygen-vacancy-rich tungsten oxide in a vacuum tube.The sulfur defects were conducive to the adsorption and activation of N2.In neutral electrolyte of 0.1 mol L^(-1)Na2SO_(4) at-0.60 V vs.reversible hydrogen electrode,such WS2-xoffered a high Faradaic efficiency of 12.1%with a NH3generation rate of 16.38μg h-1mg-1cat..展开更多
Two-dimensional(2D)semiconductors have attracted great attention to extend Moore’s law,which motivates the quest for fast growth of high-quality materials.However,taking MoS_(2) as an example,current methods yield 2D...Two-dimensional(2D)semiconductors have attracted great attention to extend Moore’s law,which motivates the quest for fast growth of high-quality materials.However,taking MoS_(2) as an example,current methods yield 2D MoS_(2) with a low growth rate and poor quality with vacancy concentrations three to five orders of magnitude higher than silicon and other commercial semiconductors.Here,we develop a strategy of using an intermediate product of iodine as a transport agent to carry metal precursors efficiently for ultrafast growth of high-quality MoS_(2).The grown MoS_(2) has the lowest density of sulfur vacancies(~1.41×10^(12) cm^(−2))reported so far and excellent electrical properties with high on/off current ratios of 108 and carrier mobility of 175 cm^(2) V^(−1) s^(−1).Theoretical calculations show that by incorporating iodine,the nucleation barrier of MoS_(2) growth with sulfur-terminated edges reduces dramatically.The sufficient supply of precursor and low nucleation energy together boost the ultrafast growth of sub-millimeter MoS_(2) domains within seconds.This work provides an effective method for the ultrafast growth of 2D semiconductors with high quality,which will promote their applications.展开更多
基金financially supported by the National Nature Science Foundation of Jiangsu Province(BK20221259)。
文摘Transition metal sulfides have high theoretical capacities and are considered as potential anode materials for sodium-ion batteries.However,due to low inherent conductivity and significant volume expansion,the electrochemical performance is greatly limited.In this study,a nickel/manganese sulfide material(Ni_(0.96)S_(x)/MnS_(y)-NC)with adjustable sulfur vacancies and heterogeneous hollow spheres was prepared using a simple method.The introduction of a concentration-adjustable sulfur vacancy enables the generation of a heterogeneous interface between bimetallic sulfide and sulfur vacancies.This interface collectively creates an internal electric field,improving the mobility of electrons and ions,increasing the number of electrochemically active sites,and further optimizing the performance of Na~+storage.The direction of electron flow is confirmed by Density functional theory(DFT)calculations.The hollow nano-spherical material provides a buffer for expansion,facilitating rapid transfer kinetics.Our innovative discovery involves the interaction between the ether-based electrolyte and copper foil,leading to the formation of Cu_9S_5,which grafts the active material and copper current collector,reinforcing mechanical supporting.This results in a new heterostructure of Cu_9S_5 with Ni_(0.96)S_(x)/MnS_(y),contributing to the stabilization of structural integrity for long-cycle performance.Therefore,Ni_(0.96)S_(x)/MnS_(y)-NC exhibits excellent electrochemical properties following our modification route.Regarding stability performance,Ni0_(.96)S_(x)/MnS_(y)-NC demonstrates an average decay rate of 0.00944%after 10,000 cycles at an extremely high current density of 10000 mA g^(-1),A full cell with a high capacity of 304.2 mA h g^(-1)was also successfully assembled by using Na_(3)V_(2)(PO_(4))_(3)/C as the cathode.This study explores a novel strategy for interface/vacancy co-modification in the fabrication of high-performance sodium-ion batteries electrode.
基金supported by the National Natural Science Foundation of China(52272295,52071137,51977071,51802040,and 21802020)the Science and Technology Innovation Program of Hunan Province(2021RC3066 and 2021RC3067)+1 种基金Natural Science Foundation of Hunan Province(2020JJ3004 and 2020JJ4192)financial support of the Fundamental Research Funds for the Central Universities。
文摘Selective CO_(2)-to-CO photoreduction is under intensive research and requires photocatalysts with tuned microstructures to accelerate the reaction kinetics.Here,we report CuInS_(2)nanosheet arrays with sulfur vacancies(VS)grown on the two-dimensional(2D)support of Ti_(3)C_(2)T_(x)MXene for CO_(2)-to-CO photoreduction.Our results reveal that the use of Ti_(3)C_(2)T_(x)induces strong support effect,which causes the hierarchical nanosheet arrays growth of CuInS_(2)and simultaneously leads to charge transfer from CuInS_(2)to Ti_(3)C_(2)T_(x)support,resulting in VSformed in CuInS_(2).The strong support effect based on Ti_(3)C_(2)T_(x)is proven to be applicable to prepare a series of different metal indium sulfide arrays with VS.CuInS_(2)nanosheet arrays with VSsupported on Ti_(3)C_(2)T_(x)benefit the photocatalytic selective reduction of CO_(2)to CO,manifesting a remarkable over 14.8-fold activity enhancement compared with pure CuInS_(2).The experimental and computational investigations pinpoint that VSof CuInS_(2)resulting from the support effect of Ti_(3)C_(2)T_(x)lowers the barrier of the rate-limiting step of^(*)COOH→^(*)OH+^(*)CO,which is the key to the photoactivity enhancement.This work demonstrates MXene support effects and offers an effective approach to regulate the atomic microstructure of metal sulfides toward enhancing photocatalytic performance.
基金supported by the National Natural Science Foundation of China(61376011 and 51402141)Gansu Provincial Natural Science Foundation(17JR5RA198)+1 种基金the Fundamental Research Funds for the Central Universities(lzujbky-2018-119 and lzujbky-2018-ct08)Shenzhen Science and Technology Innovation Committee(JCYJ20170818155813437)。
文摘Nowadays,it is a matter of great concern to design electrode materials with excellent electrochemical performance for supercapacitors by a safe,efficient and simple method.And these characteristics are usually related to the vacancies and impurities in the electrode.To investigate the effect of the vacancies on the electrochemical properties of the supercapacitor cathode material,the uniform reduced CoNi2S4(r-CoNi2S4)nanosheets with sulfur vacancies have been successfully prepared by a one-step hydrothermal method.And the formation of sulfur vacancies are characterized by Raman,X-ray photoelectron spectroscopy and other means.As the electrode for supercapacitor,the r-CoNi2S4 nanosheet electrode delivers a high capacity of 1918.9 Fg-1 at a current density of 1 A g-1,superior rate capability(87.9%retention at a current density of 20 A g-1)and extraordinary cycling stability.Compared with the original CoNi2S4 nanosheet electrode(1226 F g-1at current density of 1 A g-1),the r-CoNi2S4 nanosheet electrode shows a great improvement.The asymmetric supercapacitor based on the r-CoNi2S4 positive electrode and activated carbon negative electrode exhibits a high energy density of 30.3 Wh kg-1 at a power density of 802.1 W kg-1,as well as excellent long-term cycling stability.The feasibility and great potential of the device in practical applications have been successfully proved by lightening the light emitting diodes of three different colors.
基金financially supported by the National Natural Science Foundation of China (NSFC 21666023, 21467019, 21701168)Natural Science Foundation of Inner Mongolia Autonomous Region of China (2021ZD11, 2019BS02015)+1 种基金Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region (NJYT-19-A01)Postsubsidy Funds for the Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials (2021PT0003)。
文摘Integrating the advantages of anion vacancies and heterostructures into the catalytic materials may increase the binding affinities to intermediates, provide more active sites, and significantly promote the activity of overall water splitting. However, the successful assembly of anion vacancies and heterostructures for high-efficiency water splitting performance is still challenging. In this work, we ingeniously present the co-construction of sulfur vacancies and heterogeneous interface into Ni_(3)S_(2)/MoS_(2) catalysts on nickel foam(NF). The introduction of sulfur vacancies and Ni_(3)S_(2)/MoS_(2) heterostructures can significantly improve electron and ion transport, effectively improve structural stability, and enhance overall water splitting activity. The obtained VSNi_(3)S_(2)/MoS_(2) catalysts(VS stands for sulfur vacancies) exhibit superior OER and HER activities,and the overpotentials for OER and HER are 180 and 71 mV at 10 mA·cm^(-2), respectively. Furthermore, a low water splitting voltage of 1.46 V is required at 10 mA·cm^(-2) for the VS-Ni_(3)S_(2)/MoS_(2) catalysts, which is considerably lower than most that of water splitting electrocatalysts currently reported. This work offers an effective mean for the preparation of catalysts with both anion vacancies and heterostructures for achieving high-performance alkaline overall water splitting.
基金The research was sponsored by the National Natural Science Foundation of China(Nos.52172101 and 51872240)the National Key R&D Program for International Cooperation(No.2021YFE0115100)+2 种基金Shaanxi Province Key Research and Develop-ment Program(No.2021ZDLGY14-08)the Fundamental Research Funds for the Central Universities(No.3102019JC005)the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515110228).The authors thank the Analysis and Test Center of Northwestern Polytechnical University and Shaanxi Materials Analysis and Research Center for XPS,SEM,and TEM characterizations.
文摘To suppress the inner charge recombination and inject vast electrons,CdTe nanocrystals are embedded into ultrathin ZnIn_(2)S_(4) nanosheets to construct ZnIn_(2)S_(4)/CdTe heterostructures,where the nanocrystals are generated by a laser irradiation method.The optimal ZnIn_(2)S_(4)/CdTe heterojunction exhibits an excellent catalytic activity of 24.3 mmol/h/g,which is relatively high among the ZnIn_(2)S_(4)-based photocatalysts with-out noble metals.This enhancement is ascribed to a win-win mechanism of nanoscale heterojunctions and sulfur vacancies.The strong electron coupling effect,which is verified by density functional the-ory(DFT)calculations,impels the photo-generated electrons transfer from CdTe to ZnIn_(2)S_(4),boosting the charge separation.Meanwhile,the sulfur vacancies existing in ZnIn_(2)S_(4) can capture photoelectrons and act as active sites,facilitating the H_(2) generation reaction.In addition,the ZnIn_(2)S_(4) base and the ZnIn_(2)S_(4)/CdTe heterojunction also possess an evident photothermal effect and renewable cycle phenomena,enhancing the photocatalytic performance.This research provides new insights into the regulation of charge transfer through embedding nanocrystals.
基金supported by the Natural Science Foundation of Jiangsu Province(BK20201343 and BK20221539)China Postdoctoral Science Foundation(No.2018T110442 and 2017M610296)+3 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX22_2341)National Natural Science Foundation of China(No.52003191 and 21201083)the Open Project Program of Fujian Key Laboratory of Novel Functional Textile Fibres and Materials,Minjiang University,China(No.FKLTFM1902 and FKLTFM2005)the Open Project Program of State Key Laboratory of Molecular Engineering of Polymers,Hehai University,China(No.K2022-31).
文摘Yarn-based batteries with the dual functions of wearable and energy storage have demonstrated promising potential in wearable energy textiles.However,it is still an urgent problem to construct efficient and flexible electrodes while optimize the configuration of yarn-based batteries to maintain excellent electrochemical performance under different mechanical deformations.Herein,NiCo_(2)S_(4-x) nanotube arrays with tunable S-vacancies are constructed on carbon yarn(CY)(NiCo_(2)S_(4-x)@CY)by a facile hydrothermal strategy.The aqueous zinc-ion batteries(ZIBs)with NiCo_(2)S_(4-x)@CY as cathodes exhibit exceptional discharge capacity(271.7 mAh g^(-1))and outstanding rate performance(70.9%capacity retention at 5 A g^(-1)),and reveal a maximum power density of 6,059.5 W kg^(-1) and a maximum energy density of 432.2 Wh kg^(-1).It is worth noting that the tunable S-vacancies promote the surface reconfiguration and phase transitions of NiCo_(2)S_(4-x),thereby enhancing the conductivity and charge storage kinetics.The high reactivity and cycling stability of NiCo_(2)S_(4-x)@CY can be related to the discharge products of S-doped NiO and CoO.Furthermore,flexible stretchable yarn-based ZIBs with wrapped yarn structures are constructed and exhibit excellent tensile stability and durability under a variety of mechanical deformations.As a proof of concept,the ZIBs integrated into the fabric show excellent electrochemical performance even in response to simultaneous stretching and bending mechanical deformations.The proposed strategy provides novel inspiration for the development of highly efficient and economical yarn-based ZIBs and wearable energy textiles.
基金National Key Research And Development Program(No.2016YFB0901600)CAS Center for Excellence in Superconducting Electronics+3 种基金the Key Research Program of Chinese Academy of Sciences(Nos.QYZDJ-SSWJSC013 and KGZD-EW-T06)National Natural Science Foundation of China(Nos.21871008 and 21801247)Jingdezhen Science and Technology Bureau(No.20192GYZD008-21)Science Foundation for Youth Scholar of State Key Laboratory of High Performance Ceramics and Superfine Microstructures(No.SKL 201804)。
文摘Due to the relatively sluggish charge carrier separation in metal sulfides,the photocatalytic activity of them is still far lower than expected.Herein,sulfur vacancies and in-plane SnS_(2)/SnO_(2) heterojunction were successfully introduced into the SnS_(2) nanosheets through high energy ball-milling.These defective structures were studied by the electron paramagnetic resonance,Raman spectra,X-ray photoelectron spectroscopy,and high-resolution transmission electron microscope analyses.The sulfur vacancies and in-plane heterojunctions strongly accelerate the separation of photoexcited electron-hole pairs,as confirmed by the photo luminesce nce emission spectra and time-resolved photoluminescence decay spectra.The introduction of sulfur vacancies and in-plane heterojunction in SnS_(2) nanosheets results in roughly six times higher photodegrading rate for methyl orange and four times higher photocatalytic reduction rate of Cr6+than those of pure SnS_(2) nanosheets.
基金financially supported by the National Natural Science Foundation of China(Nos.52070046,52122009,51808140and 51838005)the Introduced of Innovative R&D Team Project under the“Pearl River Talent Recruitment Program”of Guangdong Province(No.2019ZT08L387)+1 种基金the Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(Young Scholar)the support from the BL14W1beamline of Shanghai Synchrotron Radiation Facility(SSRF,China)。
文摘Peroxymonosulfate(PMS)activation in heterogeneous processes is a promising water treatment technology.Nevertheless,the high energy consumption and low efficiency during the reaction are ineluctable,due to electron cycling rate limitation.Herein,a new strategy is proposed based on a quantum dots(QDs)/PMS system.Co-ZnS QDs are synthesized by a water phase coprecipitation method.The inequivalent lattice-doping of Co for Zn leads to the generation of surface sulfur vacancies(SVs),which modulates the surface of the catalyst to form an electronic nonequilibrium surface.Astonishingly,the plasticizer micropollutants can be completely degraded within only tens of seconds in the Co-Zn S QDs/PMS system due to this type of surface modulation.The interfacial reaction mechanism is revealed that pollutants tend to be adsorbed on the cobalt metal sites as the electron donors,where the internal electrons of pollutants are captured by the metal species and transferred to the surface SVs.Meanwhile,PMS adsorbed on the SVs is reduced to radicals by capturing electrons,achieving effective electron recovery.Dissolved oxygen(DO)molecules are also easily attracted to catalyst defects and are reduced to O_(2)^(·-),further promoting the degradation of pollutants.
基金supported by the start-up funding to H.Xu by Changzhou University(No.ZMF22020055)Advanced Catalysis and Green Manufacturing Collaborative Innovation Center,Changzhou University for financial support。
文摘Transition metal sulfides are demonstrated to play an increasingly important role in boosting the deployment of ecofriendly electrocatalytic energy conversion technologies.It is also widely recognized that the introduction of vacancies is now becoming an important and valid approach to promote the electrocatalytic performance.In this review,the significance of sulfur vacancies on the enhancement of catalytic performance via four main functionalities,including tuning the electronic structure,tailoring the active sites,improving the electrical conductivity,and regulating surface reconstruction,is comprehensively summarized.Many effective strategies for the sulfur vacancy engineering,such as plasma treatment,heteroatom doping,and chemical reduction are also comprehensively provided.Subsequently,recent achievements in sulfur vacancy fabrication on various hotspot electrocatalytic reactions are also systematically discussed.Finally,a summary of the recent progress and challenges of this interesting field are organized,which hopes to guide the future development of more efficient metal sulfide electrocatalysts.
基金supported by the National Natural Science Foundation of China(No.U20A201293)the Ningbo Ma-jor Special Project“Science and Technology Innovation 2025”(No.2020Z023),and the National Key Research and Development Pro-gram(No.2021YFB3201100).
文摘Magnetron-sputtered MoS_(2) has applications in piezoresistive functional materials research owing to its unique nanostructure.However,the controlled incorporation of sulfur vacancies and realization of en-hanced piezoresistive performance remain significant challenges.In this work,the direct growth of large-area MoS_(2) films with tunable sulfur vacancy concentrations was successfully achieved via magnetron sputtering at various temperatures.Microstructural analysis revealed that the application of strain al-tered the number of conductive channels between the vertical MoS_(2) nanosheets,changing the measured resistance and leading to excellent piezoresistive properties.More importantly,the unsaturated electrons due to the sulfur vacancies increased the in-plane carrier concentration of the MoS_(2)nanosheets.A de-position temperature of 50℃afforded the highest concentrations of sulfur vacancies and carriers.These MoS_(2)films possessed a carrier concentration of 6.58×10^(17)cm^(−3),which was 40.9%higher than that ob-tained at 150°C,and displayed superior piezoresistive performance.The films exhibited high gage factors of 2.66 and 23.22 under tensile and compressive strain of≤0.29%,respectively.These values were 118%and 323%higher,respectively,than those obtained for films deposited at 150°C.This work provides an effective route for modulating and mass producing MoS_(2)-based piezoresistive electronic devices.
基金the support of the National Natural Science Foundation of China(51702087,21673066)the Project funded by the China Postdoctoral Science Foundation(2019M652516)。
文摘Structure manipulation of photocatalysts at an atomic scale is a promising way to improve its photocatalytic performance.Herein,we realize the anchoring of single Ni atoms on the ZnIn_(2)S_(4) nanosheets with rich sulfur vacancies.Experimental results demonstrate that single Ni atoms induce the formation of NiO-M(Zn/In) atomic interface,which can efficiently promote the carriers separation and prolong the carrier life time.In addition,in situ electron spin resonance spectroscopy(ESR) confirms that the single Ni atoms act as an electron trapping center for protons reduction.As a result,the single Ni atoms decorated ZnIn_(2)S_(4) nanosheets with rich sulfur vacancies(Ni/ZnIn_(2)S_(4)-RVs) shows a hydrogen evolution rate up to 89.4 μmol h^(-1), almost 5.7 and 2.3 times higher compared to that of ZnIn_(2)S_(4) nanosheets with poor sulfur vacancies and rich sulfur vacancies(denoted as ZnIn_(2)S_(4)-PVs and ZnIn_(2)S_(4)-RVs).This work opens up a new perspective manipulating the single-atom cocatalyst and sulfur vacancy on sulfide supports for improving photocatalytic hydrogen evolution.
基金supported by the National Key Research and Development Program of China(2020YFA0715000)the National Natural Science Foundation of China(52127816)+2 种基金Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory(XHT2020-003)the China Postdoctoral Science Foundation(2021 M692490)the Fundamental Research Funds for the Central Universities(WUT:2020III029,2020IVA100).
文摘Rational design and construction of highly efficient nonprecious electrocatalysts for oxygen reduction and alcohols oxidation reactions(ORR,AOR)are extremely vital for the development of direct oxidation alkaline fuel cells,metal-air batteries,and water electrolysis system involving hydrogen and value-added organic products generation,but they remain a great challenge.Herein,a bifunctional electrocatalyst is prepared by anchoring CuS/NiS_(2)nanoparticles with abundant heterointerfaces and sulfur vacancies on graphene(Cu_(1)Ni_(2)-S/G)for ORR and AOR.Benefiting from the synergistic effects between strong interfacial coupling and regulation of the sulfur vacancies,Cu_(1)Ni_(2)-S/G achieves dramatically enhanced ORR activity with long term stability.Meanwhile,when ethanol is utilized as an oxidant for AOR,an ultralow potential(1.37 V)at a current density of 10 mA cm-2 is achieved,simultaneously delivering a high Faradaic efficiency of 96%for ethyl acetate production.Cu_(1)Ni_(2)-S/G also exhibits catalytic activity for other alcohols electrooxidation process,indicating its multifunctionality.This work not only highlights a viable strategy for tailoring catalytic activity through the synergetic combination of interfacial and vacancies engineering,but also opens up new avenues for the construction of a self-driven biomass electrocatalysis system for the generation of value-added organic products and hydrogen under ambient conditions.
文摘Hydrogen generation and related energy applications heavily rely on the hydrogen evolution reaction(HER),which faces challenges of slow kinetics and high overpotential.Efficient electrocatalysts,particularly single-atom catalysts (SACs) on two-dimensional (2D) materials,are essential.This study presents a few-shot machine learning (ML) assisted high-throughput screening of 2D septuple-atomic-layer Ga_(2)CoS_(4-x)supported SACs to predict HER catalytic activity.Initially,density functional theory (DFT)calculations showed that 2D Ga_(2)CoS4is inactive for HER.However,defective Ga_(2)CoS_(4-x)(x=0–0.25)monolayers exhibit excellent HER activity due to surface sulfur vacancies (SVs),with predicted overpotentials (0–60 mV) comparable to or lower than commercial Pt/C,which typically exhibits an overpotential of around 50 m V in the acidic electrolyte,when the concentration of surface SV is lower than 8.3%.SVs generate spin-polarized states near the Fermi level,making them effective HER sites.We demonstrate ML-accelerated HER overpotential predictions for all transition metal SACs on 2D Ga_(2)CoS_(4-x).Using DFT data from 18 SACs,an ML model with high prediction accuracy and reduced computation time was developed.An intrinsic descriptor linking SAC atomic properties to HER overpotential was identified.This study thus provides a framework for screening SACs on 2D materials,enhancing catalyst design.
基金supported by the National Natural Science Foundation of China (No 90922022)the NCETFJ Program (No. HX2006-103)+1 种基金the Science and Technology Foundation of Fujian Education Bureau (No. JA08019)the Foundation of State Key Laboratory of Coal Combustion (No. FSKLCC0814)
文摘First-principles calculations based on density functional theory (DFT) and the generalized gradient approximation (GGA) have been used to study the adsorption of CO molecule on the perfect and defective FeS 2 (100) surfaces. The defective Fe 2 S(100) surfaces are caused by sulfur deficiencies. Slab geometry and periodic boundary conditions are employed with partial relaxations of atom positions in calculations. Two molecular orientations, Cand O-down, at various distinct sites have been considered. Total energy calculations indicated that no matter on perfect or deficient surfaces, the Fe position is relatively more favored than the S site with the predicted binding energies of 120.8 kJ/mol and 140.8 kJ/mol, respectively. Moreover, CO was found to be bound to Fe atom in vertical configuration. The analysis of density of states and vibrational frequencies before and after adsorption showed clear changes of the C–O bond.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61774064,61974048,and 61851406)。
文摘A facile method of combining the defect engineering with the dielectric-screening effect is proposed to improve the electrical performance of MoS_(2) transistors. It is found that the carrier mobility of the transistor after the sulfur treatment on the MoS_(2) channel is greatly enhanced due to the reduction of the sulfur vacancies during vulcanization of MoS_(2).Furthermore, as compared to those transistors with HfO2 and SiO2 as the gate dielectric, the Al2O3-gate dielectric MoS_(2) FET shows a better electrical performance after the sulfur treatment, with a lowered subthreshold swing of 179.4 m V/dec,an increased on/off ratio of 2.11 × 10^(6), and an enhanced carrier mobility of 64.74 cm^(2)/V·s(about twice increase relative to the non-treated MoS_(2) transistor with SiO2 as the gate dielectric). These are mainly attributed to the fact that a suitable k-value gate dielectric can produce a dominant dielectric-screening effect overwhelming the phonon scattering, increasing the carrier mobility, while a larger k-value gate dielectric will enhance the phonon scattering to counteract the dielectricscreening effect, reducing the carrier mobility.
基金supported by the National Natural Science Foundation of China(no.21871206).
文摘Developing a selective hydrogenation strategy over a low-cost electrocatalyst,especially with an inexpensive and safe hydrogen source for efficient synthesis of aminoareneswith fragile functional groups,is extremely desirable.Herein,using H_(2)O as the hydrogen source,Ti mesh-supported Co_(3)S_(4)ultrathin nanosheets with sulfur vacancies(denoted as Co_(3)S_(4−x)NS)have been demonstrated to be a highly efficient cathode for selective transfer hydrogenation of nitroarenes to corresponding aminoarenes at low potential.D_(2)O-labeling experiments confirmed the hydrogen origin.Without sulfur vacancies,the products were a mixture of aminoarenes and azoxyareneswith lowselectivity.This method can deliver a variety of aminoarenes with outstanding selectivity and excellent functional group compatibility with highly reducible groups(e.g.,C–I,C–Br,C=O,C=C,C=N,C≡N,and C≡C).The experimental and theoretical results have revealed that sulfur vacancies can enhance the selective specific adsorption of the nitro group and promote intrinsic activity to form active hydrogen from water electrolysis,thus resulting in high selectivity and outstanding fragile functional groups tolerance.
基金supported by the National Natural Science Foundation of China(No.5197105852071072)the Fundamental Research Funds for the Central Universities(Nos.N182312007 and N2023001)。
文摘Zeolite Imidazole Framework(ZIF)has the advantages of large specific surface area,high porosity,and easy functionalization,so it looked like one of the most promising energy storage and conversion materials.In the meantime,transition metal oxides and sulfides have been widely used in environmental and energy conversion applications.Hence,a NaOH-assisted thioacetamide etching strategy is,therefore,designed with the metal-organic framework as precursor to realize the hollow nanostructure of ZIF bimetallic sulfide(Sx-CoCd-350)with abundant sulfur vacancies for enhanced catalysts oxygen evolution reaction(OER)/hydrogen evolution reaction(HER)performance and capacitance performance of capacitor.The overpotential of S_(2)-CoCd-350 in the OER process is 355 m V at 50 m A cm^(-2),which is substantially lower than other reported ZIF-based catalysts.S_(2)-CoCd-350 has an overpotential of 84 m V at 10 m A cm^(-2)when employed as HER catalyst.Furthermore,the S_(2)-CoCd-350 electrode did not alter appreciably during a long-term durability test of more than 10 h.More impressively,S_(2)-Co Cd-350 matches the activated carbon(AC)electrode with excellent capacitance performance 1220μWh cm^(-2)energy density(at 3370μW cm^(-2))and 25,000μW cm^(-2)(at 700μWh cm^(-2))maximum power density.In addition,the assembled supercapacitor has excellent cycling stability.
基金supported by the National Natural Science Foundation of China(52072196)the Major Basic Research Program of the Natural Science Foundation of Shandong Province(ZR2020ZD09)。
文摘MoS_(2)is a promising electrocatalyst because of its natural abundance and outstanding electrochemical stability.However,the poor conductivity and low activity limit its catalytic performance;furthermore,MoS_(2)is unable to satisfy the requirements of most industrial applications.In this study,to obtain a P-doped MoS_(2)catalyst with S vacancy defects,P is inserted into the MoS_(2)matrix via a solid phase ion exchange at room temperature.The optimal P-doping amount is 11.4 wt%,and the resultant catalyst delivers excellent electrocatalytic properties for the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)with the corresponding overpotentials of 93 and 316 mV at 10 mA cm^(-2) in an alkaline solution;these values surpass the overpotentials of most previously reported MoS_(2)-based materials.Theoretical calculations and results demonstrate that the synergistic effect of the doped P,which forms active centers in the basal plane of MoS_(2),and S vacancy defects caused by P doping intensifies the intrinsic electronic conductivity and electrocatalytic activity of the catalyst.Density functional theory calculations demonstrate that P optimizes the free energy of the MoS_(2)matrix for hydrogen adsorption,thereby considerably increasing the intrinsic activity of the doped catalyst for the HER compared with that observed from pristine MoS_(2).The enhanced catalytic activity of P-doped MoS_(2)for the OER is attributed to the ability of the doped P which facilitates the adsorption of hydroxyl and hydroperoxy intermediates and reduces the reaction energy barrier.This study provides a new environmentally friendly and convenient solid-phase ion exchange method to improve the electrocatalytic capability of two-dimensional transition-metal dichalcogenides in largescale applications.
基金supported by the National Natural Science Foundation of China (21874079)the Natural Science Foundation for Outstanding Young Scientists of Shandong Province (ZR2018JL011)+3 种基金the Key R&D Project of Shandong Province (GG201809230180)Taishan Scholars Program of Shandong Province (tsqn201909088)the Outstanding Youth Innovation Team of Universities in Shandong Province (2019KJA027)the Science & Technology Fund Planning Project of Shandong Colleges and Universities (J16LA13 and J18KA112)。
文摘Seeking catalysts with high electrocatalytic activity for ambient-condition N2 reduction reaction (NRR) remains an ongoing challenge due to the chemical inertness of N2.Herein,defect-rich WS2 nanosheets (WS2-x) were designed as an efficient electrocatalyst for NRR,which were prepared via vulcanizing the oxygen-vacancy-rich tungsten oxide in a vacuum tube.The sulfur defects were conducive to the adsorption and activation of N2.In neutral electrolyte of 0.1 mol L^(-1)Na2SO_(4) at-0.60 V vs.reversible hydrogen electrode,such WS2-xoffered a high Faradaic efficiency of 12.1%with a NH3generation rate of 16.38μg h-1mg-1cat..
基金This work was supported by the National Key R&D Program(2018YFA0307300)the National Natural Science Foundation of China(51991343,51991340,52188101 and 51920105002)+3 种基金the China Postdoctoral Science Foundation(2021M701948)the National Science Fund for Distinguished Young Scholars(52125309)Guangdong Innovative and Entrepreneurial Research Team Program(2017ZT07C341)Shenzhen Basic Research Project(JCYJ20200109144616617 and JCYJ20220818101014029).
文摘Two-dimensional(2D)semiconductors have attracted great attention to extend Moore’s law,which motivates the quest for fast growth of high-quality materials.However,taking MoS_(2) as an example,current methods yield 2D MoS_(2) with a low growth rate and poor quality with vacancy concentrations three to five orders of magnitude higher than silicon and other commercial semiconductors.Here,we develop a strategy of using an intermediate product of iodine as a transport agent to carry metal precursors efficiently for ultrafast growth of high-quality MoS_(2).The grown MoS_(2) has the lowest density of sulfur vacancies(~1.41×10^(12) cm^(−2))reported so far and excellent electrical properties with high on/off current ratios of 108 and carrier mobility of 175 cm^(2) V^(−1) s^(−1).Theoretical calculations show that by incorporating iodine,the nucleation barrier of MoS_(2) growth with sulfur-terminated edges reduces dramatically.The sufficient supply of precursor and low nucleation energy together boost the ultrafast growth of sub-millimeter MoS_(2) domains within seconds.This work provides an effective method for the ultrafast growth of 2D semiconductors with high quality,which will promote their applications.