The oxygen evolution reaction(OER)is a half-reaction of water electrolysis,and the OER performance of an electrocatalyst is significantly related to its energy conversion efficiency.Due to their high OER activity,tran...The oxygen evolution reaction(OER)is a half-reaction of water electrolysis,and the OER performance of an electrocatalyst is significantly related to its energy conversion efficiency.Due to their high OER activity,transition metal-based nanomaterials have become potential low-cost substitutes for Ir/Ru-based OER electrocatalysts in an alkaline environment.Herein,holey Fe3O4-coupled Ni(OH)2 sheets(Ni(OH)2-Fe H-STs)were easily achieved by a simple mixed-cyanogel hydrolysis strategy.The two-dimensional(2D)Ni(OH)2-Fe H-STs with ca.1 nm thickness have a high specific surface area,abundant unsaturated coordination atoms,and numerous pores,which are highly favorable for electrocatalytic reactions.Meanwhile,the introduction of Fe improves the conductivity and regulates the electronic structure of Ni.Due to their special structural features and synergistic effect between the Fe and Ni atoms,Ni(OH)2-Fe H-STs with an optimal Ni/Fe ratio show excellent OER activity in a 1 M KOH solution,which significantly exceeds that of the commercial RuO2 nanoparticle electrocatalyst.Furthermore,Ni(OH)2-Fe H-STs can be grown on nickel foam(NF),and the resulting material exhibits enhanced OER activity,such as a small overpotential of 200 mV and a small Tafel slope of 56 mV dec−1,than that of Ni(OH)2-Fe H-STs without NF.展开更多
Recently, the surface chemical functionalization and morphology control of precious metal nanostructures have been recognized as two efficient strategies for improving their electroactivity and/or selectivity. In this...Recently, the surface chemical functionalization and morphology control of precious metal nanostructures have been recognized as two efficient strategies for improving their electroactivity and/or selectivity. In this work, 1, 10-phenanthroline monohydrate(PM) functionalized Pt nanodendrites(Pt-NDs) on carbon cloth(CC)(denoted as PM@Pt-NDs/CC) and polyethylenimine(PEI) functionalized Pt-NDs on CC(denoted as PEI@Pt-NDs/CC) are successfully achieved by immersing Pt-NDs/CC into PM and PEI aqueous solutions, respectively. PEI functionalization of Pt-NDs/CC improves its electroactivity for hydrogen evolution reaction(HER) due to local proton enrichment whereas PM functionalization of Pt-NDs/CC improves its electroactivity for formic acid oxidation reaction(FAOR) by facilitating dehydrogenation pathway. With such high activity, a two-electrode electrolyzer is assembled using PM@Pt-NDs/CC as the anodic electrocatalyst and PEI@Pt-NDs/CC as the cathodic electrocatalyst for electrochemical reforming of formic acid, which only requires 0.45 V voltage to achieve the current density of 10 mA cm^(-1) for highpurity hydrogen production, much lower than conventional water electrolysis(1.59 V). The work presents an example of interfacial engineering enhancing electrocatalytic activity and indicates that electrochemical reforming of formic acid is an energy-saving electrochemical method for high-purity hydrogen production.展开更多
III-Vsemiconductor nanocrystals rarely exist as spherical inclusions inside glasses, due to difficulties during their preparation, such as high toxic reagents or fast oxidation under usual glass technology temperature...III-Vsemiconductor nanocrystals rarely exist as spherical inclusions inside glasses, due to difficulties during their preparation, such as high toxic reagents or fast oxidation under usual glass technology temperatures. In this article a sol-gel method for synthesis of InP nanocrystals embedded in silica glasses was described. Gels were synthesized by hydrolysis of a complex solution of Si(OC 2 H 5 ) 4 , InCl 3 4H 2 O and PO(OC 2 H 5 ) 3 . Then, the gels were heated at 600 o C in the presence of H 2 gas to form fine cubic InP crystallites. Raman spectrum showed InP longitudinal-optic mode (342cm -1 ) and transverse-optic mode (303cm -1 ). The size of InP nanocrystals was found to be from 2 to 8 nm in diameter by transmission electron microscopy. A strong photoluminescence with peaks at, 606, 730nm 856 nm was observed from 3InP/100SiO 2 nanocompositions. The temperature-and excitation power-dependent PL spectra from the nanocomposition are measured in order to confirm the origin of the PL spectra. These behaviors of the three peaks emissions suggest that 606, 733, and 856 nm emissions do not have the same origin. The PL with peak at 856nm arise from the cubic InP nanocrystallites embedded in the SiO 2 gel glasses. The 605 and 732 nm emissions may arise from the SiO 2 gel glass matrix or the interface between the InP crystallite core and SiO2 glass matrix.展开更多
A titanocene-ferrocenyl complex, （5-ferrocenyl-2-hydroxybenzenecarboxylato- O,O′）-bis（methylcyclopentadienyl）titanium（IV） 4, and an unexpected ionic complex, [C7H8NO3]- [（C5H5）Fe（C5H4）SO3]·H2O3 were sy...A titanocene-ferrocenyl complex, （5-ferrocenyl-2-hydroxybenzenecarboxylato- O,O′）-bis（methylcyclopentadienyl）titanium（IV） 4, and an unexpected ionic complex, [C7H8NO3]- [（C5H5）Fe（C5H4）SO3]·H2O3 were synthesized and characterized by IR, ^1H NMR and elemental analysis. Compound 3 is of triclinic, space group P1 with a = 5.954（2）, b = 13.208（5）, c = 13.252（5） A, α = 60.993（7）,β = 84.342（8）,γ = 86.933（8）°, Z = 2, V = 906.8（6）A^3, Dc = 1.601 g/cm^3, μ（MoKα） = 0.987 mm^-1, F（000） = 452, the final R = 0.0647 and wR = 0.1333 for 2311 observed reflections （I 〉 2σ（I））. Compound 4 belongs to the monoclinic system, space group P2 1/c with α = 14.3310（9）, b = 12.5065（8）, c = 12.9406（10） A, β = 95.101（4）°, Z = 4, V = 2310.2（3） A^3, Dc = 1.513 g/cm^3, μ（MoKα） = 1.004 mm^-1, F（000） = 1088, the final R = 0.0461 and wR = 0.1048 for 2112 observed reflections （1 〉 2σ（I））.展开更多
Both structure and interface engineering are highly effective strategies for enhancing the catalytic activity and selectivity of precious metal nanostructures.In this work,we develop a facile pyrolysis strategy to syn...Both structure and interface engineering are highly effective strategies for enhancing the catalytic activity and selectivity of precious metal nanostructures.In this work,we develop a facile pyrolysis strategy to synthesize the high-quality holey platinum nanotubes(Pt-H-NTs)using nanorods-like Pt^(Ⅱ)-phenanthroline(PT)coordination compound as self-template and self-reduction precursor.Then,an up-bottom strategy is used to further synthesize polyallylamine(PA)modified Pt-H-NTs(Pt-HNTs@PA).PA modification sharply promotes the catalytic activity of Pt-H-NTs for the formic acid electrooxidation reaction(FAEOR)by the direct reaction pathway.Meanwhile,PA modification also elevates the catalytic activity of Pt-H-NTs for the hydrogen evolution reaction(HER)by the proton enrichment at electrolyte/electrode interface.Benefiting from the high catalytic activity of Pt-H-NTs@PA for both FAEOR and HER,a two-electrode FAEOR boosted water electrolysis system is fabricated by using Pt-H-NTs@PA as bifunctio nal electrocatalysts.Such FAEOR boosted water electrolysis system only requires the operational voltage of 0.47 V to achieve the high-purity hydrogen production,showing an energy-saving hydrogen production strategy compared to traditional water electrolysis system.展开更多
The selective electrochemical conversion of glycerol into value-added products is a green and sustainable strategy for the biomass utilization.In this work,Au nanowires(Au-NW)modified with polyethyleneimine(PEI)molecu...The selective electrochemical conversion of glycerol into value-added products is a green and sustainable strategy for the biomass utilization.In this work,Au nanowires(Au-NW)modified with polyethyleneimine(PEI)molecule(Au-NW@PEI)is obtained by an up-bottom post-modification approach.Physical characterization,molecular dynamics simulation and density functional theory demonstrate that the loose-packed PEI monolayer firmly and uniformly distribute on the Au-NW surface due to the strong Au-N interaction.Electrochemical experiments and product analysis display that PEI modification significantly enhance the electro-activity of Au-NW for the glycerol electro-oxidation reaction(GEOR)due to the electronic effect.Meanwhile,the steric hindrance and electrostatic effect of PEI layer make the optimizing adsorption of intermediates possible.Therefore,the selectivity of C3 product glyceric acid over Au-NW@PEI is increased by nearly 20%.The work thus indicates that the rational design of metal-organic interface can effectively elevate the electro-activity and selectivity of Au nanostructures,which may have wide application in biomass development.展开更多
We present a strategy that effectively modulate the d-band electronic structure of the active center by strain effect and interatomic orbital hybridization.This strategy efficiently promotes the kinetic process of the...We present a strategy that effectively modulate the d-band electronic structure of the active center by strain effect and interatomic orbital hybridization.This strategy efficiently promotes the kinetic process of the ethanol oxidation reaction(EOR)in alkaline media.In the intermetallic Pd_(3)Pb nanowires,the introduction of Pb not only causes the lattice expansion of Pd but also achieves the interatomic orbital hybridization bonding with Pd.Such interatomic orbital hybridization effect and tensile strain effect can effectively achieve a co-regulation of the d-band electronic structure of Pd,which directly affects the adsorption behavior of intermediate on Pd for EOR.Hence,the intermetallic Pd_(3)Pb nanowires demonstrate enhanced EOR activity and anti-poisoning ability against CO_(ads).Theoretical calculations show that the enhanced OH^(*)adsorption ability and the low energy barrier for the oxidative dehydrogenation of ethanol are the keys to high EOR activity and stability of the intermetallic Pd_(3)Pb nanowires.展开更多
Palladium(Pd) nanostructures are highly promising electrocatalysts for the carbon dioxide electrochemical reduction(CO_(2) ER). At present, it is still challenge for the synthesis of Pd nanostructures with high activi...Palladium(Pd) nanostructures are highly promising electrocatalysts for the carbon dioxide electrochemical reduction(CO_(2) ER). At present, it is still challenge for the synthesis of Pd nanostructures with high activity, selectivity and stability. In this work, a facile PdII-complex pyrolysis method is applied to synthesize the high-quality one-dimensional heterostructured Pd/Pd O nanowires(Pd/Pd O H-NWs).The as-prepared Pd/Pd O H-NWs have a large electrochemically active surface area, abundant defects and Pd/Pd O heterostructure. Electrochemical measurement results reveal that Pd/Pd O H-NWs exhibit up to 94% CO Faraday efficiency with a current density of 11.6 m A cm^(-2) at an applied potential of -0.8 V. Meanwhile, Pd/Pd O H-NWs can achieve a stable catalytic process of 12 h for CO_(2) ER. Such outstanding CO_(2) ER performance of Pd/Pd O H-NWs has also been verified in the flow cell test. The density functional theory calculations indicate that Pd/Pd O heterostructure can significantly weaken the CO adsorption on Pd sites, which improves the CO tolerance and consequently enhances the catalytic performance of Pd/Pd O H-NWs for CO_(2) ER. This work highlights a facile complex pyrolysis strategy for the synthesis of Pd-based CO_(2) ER catalysts and provides a new application instance of metal/metal oxide heterostructure in electrocatalysis.展开更多
The ammonia electrolysis is a highly efficient and energy-saving method for ultra-pure hydrogen generation, which highly relies on electrocatalytic performance of electrocatalysts. In this work, high-quality platinum(...The ammonia electrolysis is a highly efficient and energy-saving method for ultra-pure hydrogen generation, which highly relies on electrocatalytic performance of electrocatalysts. In this work, high-quality platinum(Pt) nanocubes(Pt-NCs) with 4.5 nm size are achieved by facile hydrothermal synthesis. The physical morphology and structure of Pt-NCs are exhaustively characterized, revealing that Pt-NCs with special {100} facets have excellent uniformity, good dispersity and high crystallinity. Meanwhile, the electrocatalytic performance of Pt-NCs for ammonia electrolysis are carefully investigated in alkaline solutions, which display outstanding electroactivity and stability for both ammonia electrooxidation reaction(AEOR) and hydrogen evolution reaction(HER) in KOH solution. Furthermore, a symmetric Pt-NCs||Pt-NCs ammonia electrolyzer based on bifunctional Pt-NCs electrocatalyst is constructed, which only requires 0.68 V electrolysis voltage for hydrogen generation. Additionally, the symmetric Pt-NCs||Pt-NCs ammonia electrolyzer has excellent reversible switch capability for AEOR at anode and HER at cathode, showing outstanding alternating operation ability for ammonia electrolysis.展开更多
Nanocrystals of Rh, an important member of the noble metal catalyst family, have wide applications in heterogeneous catalytic reactions. Controlling the morphology of these noble metal nanocrystals has become an effec...Nanocrystals of Rh, an important member of the noble metal catalyst family, have wide applications in heterogeneous catalytic reactions. Controlling the morphology of these noble metal nanocrystals has become an effective strategy for improving their catalytic activity and durability. In this work, well-defined Rh nanodendrites with very thin triangular branches as subunits are synthesized using a facile diethylene glycol reduction method, assisted by polyethyleneimine as a complex-forming agent and surfactant. For the first time, the methanol oxidation reaction （MOR） on Rh nanocrystals with a well-defined morphology is investigated using various electrochemical techniques in an alkaline medium. Unexpectedly, the as-prepared Rh nanodendrites, with ultrathin nanosheet subunits, exhibit superior electrocatalytic activity and durability during the MOR in an alkaline medium, indicating that Rh nanocrystals with specific morphology may be highly promising alternatives to Pt electrocatalysts in the MOR in an alkaline medium.展开更多
Electrochemical water splitting(EWS)is a highly clean and efficient method for high-purity hydrogen production.Unfortunately,EWS suffers from the sluggish and complex oxygen evolution reaction(OER)kinetics at anode.At...Electrochemical water splitting(EWS)is a highly clean and efficient method for high-purity hydrogen production.Unfortunately,EWS suffers from the sluggish and complex oxygen evolution reaction(OER)kinetics at anode.At present,the efficient,stable,and low-cost non-precious metal based OER electrocatalyst is still a great and long-term challenge for the future industrial application of EWS technology.Herein,we develop a simple and fast approach for gram-scale synthesis of flower-like cobalt-based layered double hydroxides nanosheet aggregates by ultrasonic synthesis,which show outstanding electrocatalytic performance for the oxygen evolution reaction in alkaline media,such as preeminent stability,small overpotential of 300 mV at 10 mA·cm^−2 and small Tafel slope of 110 mV·dec^−1.展开更多
Designing the low cost, active, durable, and alcohol-tolerant cathode catalysts towards the oxygen reduction reaction(ORR) is significant for the large-scale commercialization of direct alcohol fuel cells.Recently, Pd...Designing the low cost, active, durable, and alcohol-tolerant cathode catalysts towards the oxygen reduction reaction(ORR) is significant for the large-scale commercialization of direct alcohol fuel cells.Recently, Pd-based nanocrystals have attracted attention as Pt-alternative cathode catalysts towards the ORR in the alkaline electrolyte. Unfortunately, the pristine Pd-based nanocrystals lack the selectivity towards the ORR due to their inherent activity for the alcohol molecule oxidation reaction in the alkaline electrolyte. In this work, polyethyleneimine(PEI) modified Au Pd alloy nanocrystals with Au-rich Au Pd alloy cores and Pd-rich Pd Au alloy shells(AuPd@PdAu-PEI) are successfully synthesized using a traditional chemical reduction method in presence of PEI. The rotating disk electrode(RDE) technique is applied to evaluate the ORR performance of AuPd@PdAu-PEI nanocrystals. Compared with commercial Pd black,AuPd@PdAu-PEI nanocrystals show significantly enhanced activity and durability towards the ORR, and simultaneously exhibit particular alcohol tolerance towards the ORR in the alkaline electrolyte.展开更多
Inefficient electrocatalysts and high-power consumption are two thorny problems for electrochemical hydrogen(H2)production from acidic water electrolysis.Herein we report the one-pot precise synthesis of ultrafine Au ...Inefficient electrocatalysts and high-power consumption are two thorny problems for electrochemical hydrogen(H2)production from acidic water electrolysis.Herein we report the one-pot precise synthesis of ultrafine Au core-Pt Au alloy shell nanowires(Au@PtxAu UFNWs).Among them,Au@Pt_(0.077) Au UFNWs exhibit the best performance for formic acid oxidation reaction(FAOR)and hydrogen evolution reaction(HER),which only require applied potentials of 0.29 V and-22.6 m V to achieve a current density of 10 m A cm^(-2),respectively.The corresponding formic acid electrolyzer realizes the electrochemical H2 production at a voltage of only 0.51 V with 10 m A cm^(-2) current density.Density functional theory(DFT)calculations reveal that the Au-riched Pt Au alloy structure can facilitates the direct oxidation pathway of FAOR and consequently elevates the FAOR activity of Au@Pt_(0.077) Au UFNWs.This work provides meaningful insights into the electrochemical H_(2) production from both the construction of advanced bifunctional electrocatalysts and the replacement of OER.展开更多
Direct methanol fuel cells are one of the most promising alternative energy technologies in the foreseeable future, but its successful commercialization in large scale is still heavily hindered by several technical sh...Direct methanol fuel cells are one of the most promising alternative energy technologies in the foreseeable future, but its successful commercialization in large scale is still heavily hindered by several technical shortfalls, especially the undesirable activity and durability issues of electrocatalysts toward methanol oxidation reaction. In light of these challenges, the inherent advantages of unsupported Pt based nanostructures demonstrate their great potentials as durable and efficient electrocatalysts for direct methanol fuel cells. This review will summarize recent achievements of unsupported Pt-based electrocatalysts toward methanol oxidation, with highlighting the interactions between the performance and structure tailoring and composition modulating. At last, a perspective is proposed for the upcoming challenges and possible opportunities to further prompt the practical application of unsupported Pt-based electrocatalysts for direct methanol fuel cells.展开更多
The design and synthesis of high‐performance and low‐cost electrocatalysts for the hydrogen evolution reaction(HER),a key half‐reaction in water electrolysis,are essential.Owing to their modest hydrogen adsorption ...The design and synthesis of high‐performance and low‐cost electrocatalysts for the hydrogen evolution reaction(HER),a key half‐reaction in water electrolysis,are essential.Owing to their modest hydrogen adsorption energy,ruthenium(Ru)‐based nanomaterials are considered outstanding candidates to replace the expensive platinum(Pt)‐based HER electrocatalysts.In this study,we developed an adsorption‐pyrolysis method to construct nitrogen(N)‐doped graphene aerogel(N‐GA)‐supported ultrafine Ru nanocrystal(Ru‐NC)nanocomposites(Ru‐NCs/N‐GA).The particle size of the Ru‐NCs and the conductivity of the N‐GA substrate can be controlled by varying the pyrolysis temperature.Optimal experiments reveal revealed that 10 wt%Ru‐NCs/N‐GA nanocomposites require overpotentials of only 52 and 36 mV to achieve a current density of 10 mA cm^(−2) in 1 mol/L HClO4 and 1 mol/L KOH electrolytes for HER,respectively,which is comparable to 20 wt%Pt/C electrocatalyst.Benefiting from the ultrafine size and uniform dispersion of the Ru‐NCs,the synergy between Ru and the highly conductive substrate,and the anchoring effect of the N atom,the Ru‐NCs/N‐GA nanocomposites exhibit excellent activity and durability in the pH‐universal HER,thereby opening a new avenue for the production of commercial HER electrocatalysts.展开更多
The development of an efficient catalyst for formic acid electrocatalytic oxidation reaction(FAEOR)is of great significance to accelerate the commercial application of direct formic acid fuel cells(DFAFC).Herein,palla...The development of an efficient catalyst for formic acid electrocatalytic oxidation reaction(FAEOR)is of great significance to accelerate the commercial application of direct formic acid fuel cells(DFAFC).Herein,palladium phosphide(PdxPy)porous nanotubes(PNTs)with different phosphide content(i.e.,Pd3P and Pd5P2)are prepared by combining the self-template reduction method of dimethylglyoxime-Pd(II)complex nanorods and succedent phosphating treatment.During the reduction process,the self-removal of the template and the continual inside-outside Ostwald ripening phenomenon are responsible for the generation of the one-dimensional hollow and porous architecture.On the basis of the unique synthetic procedure and structural advantages,Pd3P PNTs with optimized phos phide content show outstanding electroactivity and stability for FAEOR.Im portantly,the strong electronic effect between Pd and P promotes the direct pathway of FAEOR and inhibits the occurrence of the formic acid decomposition reaction,which effectively enhances the FAEOR electroactivity of Pd3P PNTs.In view of the facial synthesis,excellent electroactivity,high stability,and unordinary selectivity,Pd3P PNTs have the potential to be an efficient anode electrocatalyst for DFAFC.展开更多
Large-scale oriented ZnO nanocone arrays were directly grown on zinc substrate through a hydrothermal reaction of Zn foil with aqueous butylamine solution (3 mol/L) at 100–180 °C for 12 h. The synthesized produc...Large-scale oriented ZnO nanocone arrays were directly grown on zinc substrate through a hydrothermal reaction of Zn foil with aqueous butylamine solution (3 mol/L) at 100–180 °C for 12 h. The synthesized products were characterized with X-ray diffraction, Raman spectrum, scanning electron microscopy and transmission electron microscopy. The results showed that the ZnO nanocones were single crystalline with the wurtzite structure and grown along the [0001] direction. The diameter of nanocones is decreased with increasing the reaction temperature. A possible growth mechanism was also proposed to account for the formation of the ZnO nanocone arrays. The photoluminescence spectra of the ZnO nanocone arrays were studied at room temperature, two UV emission bands at 377 and 396 nm assigned to free exciton emission and exciton-exciton collision, respectively, and phonon replicas associated with 2-E2 phonon were observed in the PL spectra.展开更多
Controllable self-assembly of noble metal nanocrystals is of broad interest for the development of highly active electrocatalysts. Here we report an efficient arginine-mediated hydrothermal approach for the high-yield...Controllable self-assembly of noble metal nanocrystals is of broad interest for the development of highly active electrocatalysts. Here we report an efficient arginine-mediated hydrothermal approach for the high-yield synthesis of cube-like Pt nanoassemblies （Pt-CNAs） with porous cavities and rough surfaces based on the self-assembly of zero dimensional Pt nanocrystals. In this process, arginine acts as the reductant, structure directing agent, and linker between adjacent nanocrystals. Interestingly, the Pt-CNAs exhibit single-crystal structures with dominant {100} facets, as evidenced by X-ray diffraction. Based on electrocatalytic studies, the as-synthesized Pt-CNAs exhibit improved electrocatalytic activity as well as good stability and CO tolerance in the methanol oxidation reaction. The Pt-CNA＇s good performance is attributed to their unique morphology and surface structure. We believe that the synthetic strategy outlined here could be extended to other rationally designed monometallic or bimetallic nanoassemblies for use in high performance fuel cells.展开更多
The research on electrocatalysts with relatively lower price than Pt and excellent electrocatalytic performance for the cathode oxygen reduction reaction(ORR) and anode methanol oxidation reaction(MOR) is vital for th...The research on electrocatalysts with relatively lower price than Pt and excellent electrocatalytic performance for the cathode oxygen reduction reaction(ORR) and anode methanol oxidation reaction(MOR) is vital for the development of direct methanol fuel cells(DMFCs). In this work, we develop a cyanogel-reduction method to synthesize reduced graphene oxide(rGO) supported highly dispersed PdNi alloy nanocrystals(PdNi/rGO) with high alloying degree and tunable Pd/Ni ratio. The large specific surface area and the d-band center downshift of Pd result in excellent activity of Pd4 Ni1/rGO nanohybrids for the ORR. The modification of Pd electronic structure can facilitate the adsorption of CH3 OH on Pd surface and the highly oxophilic property of Ni can eliminate/mitigate the COadsintermediates poisoning, which make PdNi/r GO nanohybrids possess superior MOR activity. In addition, rGO improve the stability of PdNi alloy nanocrystals for the ORR and MOR. Due to high activity and stability for the ORR and MOR, PdNi/rGO nanohybrids are promising to be an available bifunctional electrocatalyst in DMFCs.展开更多
Acetylene (C_(2)H_(2)) and ethylene (C_(2)H_(4)) both are important chemical raw materials and energy fuel gasses.But the effective removement of trace C_(2)H_(2)from C_(2)H_(4)and the purification of C_(2)H_(2)from c...Acetylene (C_(2)H_(2)) and ethylene (C_(2)H_(4)) both are important chemical raw materials and energy fuel gasses.But the effective removement of trace C_(2)H_(2)from C_(2)H_(4)and the purification of C_(2)H_(2)from carbon dioxide(CO_(2)) are particularly challenging in the petrochemical industry.As a class of porous physical adsorbent,metal-organic frameworks (MOFs) have exhibited great success in separation and purification of light hydrocarbon gas.Herein,we rationally designed four novel MOFs by the strategy of pore space partition(PSP) via introducing triangular tri(pyridin-4-yl)-amine (TPA) into the 1D hexagonal channels of acs-type parent skeleton.By modulating the functional groups of linear dicarboxylate linkers for the parent skeleton,a series of isoreticular PSP-MOFs (SNNU-278-281) were successfully obtained.The synergistic effects of suitable pore size and Lewis basic functional groups make these MOFs ideal C_(2)H_(2)adsorbents.The gas adsorption experimental results show that all MOFs have excellent C_(2)H_(2)uptakes.Specially,SNNU-278demonstrates a high C_(2)H_(2)uptake of 149.7 cm3/g at 273 K and 1 atm.Meanwhile,SNNU-278-281 MOFs also show extremely great C_(2)H_(2)separation from CO_(2)and C_(2)H_(4).The optimized SNNU-281 with highdensity hydroxy groups exhibits extraordinary C_(2)H_(2)/CO_(2)and C_(2)H_(2)/C_(2)H_(4)dynamic breakthrough interval times up to 31 min/g and 17 min/g under 298 K and 1 bar.展开更多
文摘The oxygen evolution reaction(OER)is a half-reaction of water electrolysis,and the OER performance of an electrocatalyst is significantly related to its energy conversion efficiency.Due to their high OER activity,transition metal-based nanomaterials have become potential low-cost substitutes for Ir/Ru-based OER electrocatalysts in an alkaline environment.Herein,holey Fe3O4-coupled Ni(OH)2 sheets(Ni(OH)2-Fe H-STs)were easily achieved by a simple mixed-cyanogel hydrolysis strategy.The two-dimensional(2D)Ni(OH)2-Fe H-STs with ca.1 nm thickness have a high specific surface area,abundant unsaturated coordination atoms,and numerous pores,which are highly favorable for electrocatalytic reactions.Meanwhile,the introduction of Fe improves the conductivity and regulates the electronic structure of Ni.Due to their special structural features and synergistic effect between the Fe and Ni atoms,Ni(OH)2-Fe H-STs with an optimal Ni/Fe ratio show excellent OER activity in a 1 M KOH solution,which significantly exceeds that of the commercial RuO2 nanoparticle electrocatalyst.Furthermore,Ni(OH)2-Fe H-STs can be grown on nickel foam(NF),and the resulting material exhibits enhanced OER activity,such as a small overpotential of 200 mV and a small Tafel slope of 56 mV dec−1,than that of Ni(OH)2-Fe H-STs without NF.
基金sponsored by Natural Science Foundation of Shaanxi Province (2020JZ-23)the Fundamental Research Funds for the Central Universities (GK201901002, GK201701007 and GK201902014)the 111 Project (B14041)。
文摘Recently, the surface chemical functionalization and morphology control of precious metal nanostructures have been recognized as two efficient strategies for improving their electroactivity and/or selectivity. In this work, 1, 10-phenanthroline monohydrate(PM) functionalized Pt nanodendrites(Pt-NDs) on carbon cloth(CC)(denoted as PM@Pt-NDs/CC) and polyethylenimine(PEI) functionalized Pt-NDs on CC(denoted as PEI@Pt-NDs/CC) are successfully achieved by immersing Pt-NDs/CC into PM and PEI aqueous solutions, respectively. PEI functionalization of Pt-NDs/CC improves its electroactivity for hydrogen evolution reaction(HER) due to local proton enrichment whereas PM functionalization of Pt-NDs/CC improves its electroactivity for formic acid oxidation reaction(FAOR) by facilitating dehydrogenation pathway. With such high activity, a two-electrode electrolyzer is assembled using PM@Pt-NDs/CC as the anodic electrocatalyst and PEI@Pt-NDs/CC as the cathodic electrocatalyst for electrochemical reforming of formic acid, which only requires 0.45 V voltage to achieve the current density of 10 mA cm^(-1) for highpurity hydrogen production, much lower than conventional water electrolysis(1.59 V). The work presents an example of interfacial engineering enhancing electrocatalytic activity and indicates that electrochemical reforming of formic acid is an energy-saving electrochemical method for high-purity hydrogen production.
文摘III-Vsemiconductor nanocrystals rarely exist as spherical inclusions inside glasses, due to difficulties during their preparation, such as high toxic reagents or fast oxidation under usual glass technology temperatures. In this article a sol-gel method for synthesis of InP nanocrystals embedded in silica glasses was described. Gels were synthesized by hydrolysis of a complex solution of Si(OC 2 H 5 ) 4 , InCl 3 4H 2 O and PO(OC 2 H 5 ) 3 . Then, the gels were heated at 600 o C in the presence of H 2 gas to form fine cubic InP crystallites. Raman spectrum showed InP longitudinal-optic mode (342cm -1 ) and transverse-optic mode (303cm -1 ). The size of InP nanocrystals was found to be from 2 to 8 nm in diameter by transmission electron microscopy. A strong photoluminescence with peaks at, 606, 730nm 856 nm was observed from 3InP/100SiO 2 nanocompositions. The temperature-and excitation power-dependent PL spectra from the nanocomposition are measured in order to confirm the origin of the PL spectra. These behaviors of the three peaks emissions suggest that 606, 733, and 856 nm emissions do not have the same origin. The PL with peak at 856nm arise from the cubic InP nanocrystallites embedded in the SiO 2 gel glasses. The 605 and 732 nm emissions may arise from the SiO 2 gel glass matrix or the interface between the InP crystallite core and SiO2 glass matrix.
基金Supported by the National Natural Science Foundation of China (20771071)the Program for New Century Excellent Talents in University of China,and Natural Science Foundation of Shaanxi Province (2007B06)
文摘A titanocene-ferrocenyl complex, （5-ferrocenyl-2-hydroxybenzenecarboxylato- O,O′）-bis（methylcyclopentadienyl）titanium（IV） 4, and an unexpected ionic complex, [C7H8NO3]- [（C5H5）Fe（C5H4）SO3]·H2O3 were synthesized and characterized by IR, ^1H NMR and elemental analysis. Compound 3 is of triclinic, space group P1 with a = 5.954（2）, b = 13.208（5）, c = 13.252（5） A, α = 60.993（7）,β = 84.342（8）,γ = 86.933（8）°, Z = 2, V = 906.8（6）A^3, Dc = 1.601 g/cm^3, μ（MoKα） = 0.987 mm^-1, F（000） = 452, the final R = 0.0647 and wR = 0.1333 for 2311 observed reflections （I 〉 2σ（I））. Compound 4 belongs to the monoclinic system, space group P2 1/c with α = 14.3310（9）, b = 12.5065（8）, c = 12.9406（10） A, β = 95.101（4）°, Z = 4, V = 2310.2（3） A^3, Dc = 1.513 g/cm^3, μ（MoKα） = 1.004 mm^-1, F（000） = 1088, the final R = 0.0461 and wR = 0.1048 for 2112 observed reflections （1 〉 2σ（I））.
基金sponsored by the National Natural Science Foundation of China(22272103)the Natural Science Foundation of Shaanxi Province(2020JZ-23,2019KJXX-021,and 2020JM269)+7 种基金the Key Research and Development Program of Shaanxi(2020SF-355)the Science and Technology Innovation Team of Shaanxi Province(2022TD-35)the University Engineering Research Center of Crystal Growth and Applications of Guangdong Province(2020GCZX005)the Special Innovative Projects of Guangdong Province(2020KTSCX125)the Shenzhen Stable Supporting Program(SZWD2021015)the Fundamental Research Funds for the Central Universities(GK202202001)the Open Foundation of Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured Materials at Guangxi University(2021GXYSOF02)the 111 Project(B14041)。
文摘Both structure and interface engineering are highly effective strategies for enhancing the catalytic activity and selectivity of precious metal nanostructures.In this work,we develop a facile pyrolysis strategy to synthesize the high-quality holey platinum nanotubes(Pt-H-NTs)using nanorods-like Pt^(Ⅱ)-phenanthroline(PT)coordination compound as self-template and self-reduction precursor.Then,an up-bottom strategy is used to further synthesize polyallylamine(PA)modified Pt-H-NTs(Pt-HNTs@PA).PA modification sharply promotes the catalytic activity of Pt-H-NTs for the formic acid electrooxidation reaction(FAEOR)by the direct reaction pathway.Meanwhile,PA modification also elevates the catalytic activity of Pt-H-NTs for the hydrogen evolution reaction(HER)by the proton enrichment at electrolyte/electrode interface.Benefiting from the high catalytic activity of Pt-H-NTs@PA for both FAEOR and HER,a two-electrode FAEOR boosted water electrolysis system is fabricated by using Pt-H-NTs@PA as bifunctio nal electrocatalysts.Such FAEOR boosted water electrolysis system only requires the operational voltage of 0.47 V to achieve the high-purity hydrogen production,showing an energy-saving hydrogen production strategy compared to traditional water electrolysis system.
基金sponsored by National Natural Science Foundation of China(No.22202130)China Postdoctoral Science Foundation(No.2022M710088)+3 种基金Science and Technology Innovation Team of Shaanxi Province(Nos.2023-CX-TD-27 and 2022TD-35)Fundamental Research Funds for the Central Universities(Nos.GK202202001 and GK202101005)Open Funds of the State Key Laboratory of Electroanalytical Chemistry(No.SKLEAC202207)the 111 Project(No.B14041)。
文摘The selective electrochemical conversion of glycerol into value-added products is a green and sustainable strategy for the biomass utilization.In this work,Au nanowires(Au-NW)modified with polyethyleneimine(PEI)molecule(Au-NW@PEI)is obtained by an up-bottom post-modification approach.Physical characterization,molecular dynamics simulation and density functional theory demonstrate that the loose-packed PEI monolayer firmly and uniformly distribute on the Au-NW surface due to the strong Au-N interaction.Electrochemical experiments and product analysis display that PEI modification significantly enhance the electro-activity of Au-NW for the glycerol electro-oxidation reaction(GEOR)due to the electronic effect.Meanwhile,the steric hindrance and electrostatic effect of PEI layer make the optimizing adsorption of intermediates possible.Therefore,the selectivity of C3 product glyceric acid over Au-NW@PEI is increased by nearly 20%.The work thus indicates that the rational design of metal-organic interface can effectively elevate the electro-activity and selectivity of Au nanostructures,which may have wide application in biomass development.
基金sponsored by the National Natural Science Foundation of China(22272103)the Science and Technology Innovation Team of Shaanxi Province(2022TD-35and 2023-CX-TD-27)+1 种基金Fundamental Research Funds for the Central Universities(GK202202001)Sanqin Scholars Innovation Teams in Shaanxi Province,China.
文摘We present a strategy that effectively modulate the d-band electronic structure of the active center by strain effect and interatomic orbital hybridization.This strategy efficiently promotes the kinetic process of the ethanol oxidation reaction(EOR)in alkaline media.In the intermetallic Pd_(3)Pb nanowires,the introduction of Pb not only causes the lattice expansion of Pd but also achieves the interatomic orbital hybridization bonding with Pd.Such interatomic orbital hybridization effect and tensile strain effect can effectively achieve a co-regulation of the d-band electronic structure of Pd,which directly affects the adsorption behavior of intermediate on Pd for EOR.Hence,the intermetallic Pd_(3)Pb nanowires demonstrate enhanced EOR activity and anti-poisoning ability against CO_(ads).Theoretical calculations show that the enhanced OH^(*)adsorption ability and the low energy barrier for the oxidative dehydrogenation of ethanol are the keys to high EOR activity and stability of the intermetallic Pd_(3)Pb nanowires.
基金supported by the National Natural Science Foundation of China(51873100)Natural Science Foundation of Shaanxi Province(2020JZ-23)+2 种基金the Fundamental Research Funds for the Central Universities(GK202101005 and 2021CBLZ004)the Innovation Team Project for Graduate Student at Shaanxi Normal University(TD2020048Y)the 111 Project(B14041)。
文摘Palladium(Pd) nanostructures are highly promising electrocatalysts for the carbon dioxide electrochemical reduction(CO_(2) ER). At present, it is still challenge for the synthesis of Pd nanostructures with high activity, selectivity and stability. In this work, a facile PdII-complex pyrolysis method is applied to synthesize the high-quality one-dimensional heterostructured Pd/Pd O nanowires(Pd/Pd O H-NWs).The as-prepared Pd/Pd O H-NWs have a large electrochemically active surface area, abundant defects and Pd/Pd O heterostructure. Electrochemical measurement results reveal that Pd/Pd O H-NWs exhibit up to 94% CO Faraday efficiency with a current density of 11.6 m A cm^(-2) at an applied potential of -0.8 V. Meanwhile, Pd/Pd O H-NWs can achieve a stable catalytic process of 12 h for CO_(2) ER. Such outstanding CO_(2) ER performance of Pd/Pd O H-NWs has also been verified in the flow cell test. The density functional theory calculations indicate that Pd/Pd O heterostructure can significantly weaken the CO adsorption on Pd sites, which improves the CO tolerance and consequently enhances the catalytic performance of Pd/Pd O H-NWs for CO_(2) ER. This work highlights a facile complex pyrolysis strategy for the synthesis of Pd-based CO_(2) ER catalysts and provides a new application instance of metal/metal oxide heterostructure in electrocatalysis.
基金sponsored by the National Natural Science Foundation of China (21875133 and 51873100)the Fundamental Research Funds for the Central Universities (GK201901002 and GK201902014)the 111 Project (B14041)。
文摘The ammonia electrolysis is a highly efficient and energy-saving method for ultra-pure hydrogen generation, which highly relies on electrocatalytic performance of electrocatalysts. In this work, high-quality platinum(Pt) nanocubes(Pt-NCs) with 4.5 nm size are achieved by facile hydrothermal synthesis. The physical morphology and structure of Pt-NCs are exhaustively characterized, revealing that Pt-NCs with special {100} facets have excellent uniformity, good dispersity and high crystallinity. Meanwhile, the electrocatalytic performance of Pt-NCs for ammonia electrolysis are carefully investigated in alkaline solutions, which display outstanding electroactivity and stability for both ammonia electrooxidation reaction(AEOR) and hydrogen evolution reaction(HER) in KOH solution. Furthermore, a symmetric Pt-NCs||Pt-NCs ammonia electrolyzer based on bifunctional Pt-NCs electrocatalyst is constructed, which only requires 0.68 V electrolysis voltage for hydrogen generation. Additionally, the symmetric Pt-NCs||Pt-NCs ammonia electrolyzer has excellent reversible switch capability for AEOR at anode and HER at cathode, showing outstanding alternating operation ability for ammonia electrolysis.
基金This work was supported by National Natural Science Foundation of China （No. 21473111）, Natural Science Foundation of Shaanxi Province （No. 2015JM2043）,and Fundamental Research Funds for the Central Universities （Nos. GK201602002 and GK201503037）.
文摘Nanocrystals of Rh, an important member of the noble metal catalyst family, have wide applications in heterogeneous catalytic reactions. Controlling the morphology of these noble metal nanocrystals has become an effective strategy for improving their catalytic activity and durability. In this work, well-defined Rh nanodendrites with very thin triangular branches as subunits are synthesized using a facile diethylene glycol reduction method, assisted by polyethyleneimine as a complex-forming agent and surfactant. For the first time, the methanol oxidation reaction （MOR） on Rh nanocrystals with a well-defined morphology is investigated using various electrochemical techniques in an alkaline medium. Unexpectedly, the as-prepared Rh nanodendrites, with ultrathin nanosheet subunits, exhibit superior electrocatalytic activity and durability during the MOR in an alkaline medium, indicating that Rh nanocrystals with specific morphology may be highly promising alternatives to Pt electrocatalysts in the MOR in an alkaline medium.
基金sponsored by the Natural Science Basic Research Plan in Shaanxi Province of China(No.2018JM5093)the Fundamental Research Funds for the Central Universities(Nos.GK201702009 and GK201901002)111 Project(No.B14041).
文摘Electrochemical water splitting(EWS)is a highly clean and efficient method for high-purity hydrogen production.Unfortunately,EWS suffers from the sluggish and complex oxygen evolution reaction(OER)kinetics at anode.At present,the efficient,stable,and low-cost non-precious metal based OER electrocatalyst is still a great and long-term challenge for the future industrial application of EWS technology.Herein,we develop a simple and fast approach for gram-scale synthesis of flower-like cobalt-based layered double hydroxides nanosheet aggregates by ultrasonic synthesis,which show outstanding electrocatalytic performance for the oxygen evolution reaction in alkaline media,such as preeminent stability,small overpotential of 300 mV at 10 mA·cm^−2 and small Tafel slope of 110 mV·dec^−1.
基金sponsored by the National Natural Science Foundation of China(21473111)Fundamental Research Funds for the Central Universities(GK201602002 and GK201701007)
文摘Designing the low cost, active, durable, and alcohol-tolerant cathode catalysts towards the oxygen reduction reaction(ORR) is significant for the large-scale commercialization of direct alcohol fuel cells.Recently, Pd-based nanocrystals have attracted attention as Pt-alternative cathode catalysts towards the ORR in the alkaline electrolyte. Unfortunately, the pristine Pd-based nanocrystals lack the selectivity towards the ORR due to their inherent activity for the alcohol molecule oxidation reaction in the alkaline electrolyte. In this work, polyethyleneimine(PEI) modified Au Pd alloy nanocrystals with Au-rich Au Pd alloy cores and Pd-rich Pd Au alloy shells(AuPd@PdAu-PEI) are successfully synthesized using a traditional chemical reduction method in presence of PEI. The rotating disk electrode(RDE) technique is applied to evaluate the ORR performance of AuPd@PdAu-PEI nanocrystals. Compared with commercial Pd black,AuPd@PdAu-PEI nanocrystals show significantly enhanced activity and durability towards the ORR, and simultaneously exhibit particular alcohol tolerance towards the ORR in the alkaline electrolyte.
基金supported by the Natural Science Foundation of Shaanxi Province(2020JZ-23)the Fundamental Research Funds for the Central Universities(GK201901002,GK202101005,2020CSLZ012 and 2019TS007)+4 种基金the Innovation Team Project for Graduate Student at Shaanxi Normal University(TD2020048Y)the Key Research and Development Program of Shaanxi(Program No.2020SF-355)the National Training Program of Innovation and Entrepreneurship for Undergraduates(S202010718130)the Open Foundation of Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured Materials at Guangxi University(2021GXYSOF02)the 111 Project(B14041)。
文摘Inefficient electrocatalysts and high-power consumption are two thorny problems for electrochemical hydrogen(H2)production from acidic water electrolysis.Herein we report the one-pot precise synthesis of ultrafine Au core-Pt Au alloy shell nanowires(Au@PtxAu UFNWs).Among them,Au@Pt_(0.077) Au UFNWs exhibit the best performance for formic acid oxidation reaction(FAOR)and hydrogen evolution reaction(HER),which only require applied potentials of 0.29 V and-22.6 m V to achieve a current density of 10 m A cm^(-2),respectively.The corresponding formic acid electrolyzer realizes the electrochemical H2 production at a voltage of only 0.51 V with 10 m A cm^(-2) current density.Density functional theory(DFT)calculations reveal that the Au-riched Pt Au alloy structure can facilitates the direct oxidation pathway of FAOR and consequently elevates the FAOR activity of Au@Pt_(0.077) Au UFNWs.This work provides meaningful insights into the electrochemical H_(2) production from both the construction of advanced bifunctional electrocatalysts and the replacement of OER.
基金financial supported by National 1000 Young Talents Program of ChinaNation Natural Science Foundation of China(21473111)+2 种基金The Innovation Foundation of Shenzhen Government(JCYJ20160408173202143)the Joint Fund of Energy Storage of Qingdao(20160012)the Innovation Research Funds of HUST(3004013109,0118013089,and 2017KFYXJJ164)
文摘Direct methanol fuel cells are one of the most promising alternative energy technologies in the foreseeable future, but its successful commercialization in large scale is still heavily hindered by several technical shortfalls, especially the undesirable activity and durability issues of electrocatalysts toward methanol oxidation reaction. In light of these challenges, the inherent advantages of unsupported Pt based nanostructures demonstrate their great potentials as durable and efficient electrocatalysts for direct methanol fuel cells. This review will summarize recent achievements of unsupported Pt-based electrocatalysts toward methanol oxidation, with highlighting the interactions between the performance and structure tailoring and composition modulating. At last, a perspective is proposed for the upcoming challenges and possible opportunities to further prompt the practical application of unsupported Pt-based electrocatalysts for direct methanol fuel cells.
文摘The design and synthesis of high‐performance and low‐cost electrocatalysts for the hydrogen evolution reaction(HER),a key half‐reaction in water electrolysis,are essential.Owing to their modest hydrogen adsorption energy,ruthenium(Ru)‐based nanomaterials are considered outstanding candidates to replace the expensive platinum(Pt)‐based HER electrocatalysts.In this study,we developed an adsorption‐pyrolysis method to construct nitrogen(N)‐doped graphene aerogel(N‐GA)‐supported ultrafine Ru nanocrystal(Ru‐NC)nanocomposites(Ru‐NCs/N‐GA).The particle size of the Ru‐NCs and the conductivity of the N‐GA substrate can be controlled by varying the pyrolysis temperature.Optimal experiments reveal revealed that 10 wt%Ru‐NCs/N‐GA nanocomposites require overpotentials of only 52 and 36 mV to achieve a current density of 10 mA cm^(−2) in 1 mol/L HClO4 and 1 mol/L KOH electrolytes for HER,respectively,which is comparable to 20 wt%Pt/C electrocatalyst.Benefiting from the ultrafine size and uniform dispersion of the Ru‐NCs,the synergy between Ru and the highly conductive substrate,and the anchoring effect of the N atom,the Ru‐NCs/N‐GA nanocomposites exhibit excellent activity and durability in the pH‐universal HER,thereby opening a new avenue for the production of commercial HER electrocatalysts.
基金supported by the National Natural Science Foundation of China(21875133 and 51873100)Natural Science Foundation of Shaanxi Province(2020JZ-23)+2 种基金the National Training Program of Innovation and Entrepreneurship for Undergraduates(S202010718130)Fundamental Research Funds for the Central Universities(GK202101005,GK202103062,and 2021CBLZ004)the 111 Project(B14041).
文摘The development of an efficient catalyst for formic acid electrocatalytic oxidation reaction(FAEOR)is of great significance to accelerate the commercial application of direct formic acid fuel cells(DFAFC).Herein,palladium phosphide(PdxPy)porous nanotubes(PNTs)with different phosphide content(i.e.,Pd3P and Pd5P2)are prepared by combining the self-template reduction method of dimethylglyoxime-Pd(II)complex nanorods and succedent phosphating treatment.During the reduction process,the self-removal of the template and the continual inside-outside Ostwald ripening phenomenon are responsible for the generation of the one-dimensional hollow and porous architecture.On the basis of the unique synthetic procedure and structural advantages,Pd3P PNTs with optimized phos phide content show outstanding electroactivity and stability for FAEOR.Im portantly,the strong electronic effect between Pd and P promotes the direct pathway of FAEOR and inhibits the occurrence of the formic acid decomposition reaction,which effectively enhances the FAEOR electroactivity of Pd3P PNTs.In view of the facial synthesis,excellent electroactivity,high stability,and unordinary selectivity,Pd3P PNTs have the potential to be an efficient anode electrocatalyst for DFAFC.
基金Supported by the National Natural Science Foundation of China (Grant No. 20573072)Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20060718010)
文摘Large-scale oriented ZnO nanocone arrays were directly grown on zinc substrate through a hydrothermal reaction of Zn foil with aqueous butylamine solution (3 mol/L) at 100–180 °C for 12 h. The synthesized products were characterized with X-ray diffraction, Raman spectrum, scanning electron microscopy and transmission electron microscopy. The results showed that the ZnO nanocones were single crystalline with the wurtzite structure and grown along the [0001] direction. The diameter of nanocones is decreased with increasing the reaction temperature. A possible growth mechanism was also proposed to account for the formation of the ZnO nanocone arrays. The photoluminescence spectra of the ZnO nanocone arrays were studied at room temperature, two UV emission bands at 377 and 396 nm assigned to free exciton emission and exciton-exciton collision, respectively, and phonon replicas associated with 2-E2 phonon were observed in the PL spectra.
文摘Controllable self-assembly of noble metal nanocrystals is of broad interest for the development of highly active electrocatalysts. Here we report an efficient arginine-mediated hydrothermal approach for the high-yield synthesis of cube-like Pt nanoassemblies （Pt-CNAs） with porous cavities and rough surfaces based on the self-assembly of zero dimensional Pt nanocrystals. In this process, arginine acts as the reductant, structure directing agent, and linker between adjacent nanocrystals. Interestingly, the Pt-CNAs exhibit single-crystal structures with dominant {100} facets, as evidenced by X-ray diffraction. Based on electrocatalytic studies, the as-synthesized Pt-CNAs exhibit improved electrocatalytic activity as well as good stability and CO tolerance in the methanol oxidation reaction. The Pt-CNA＇s good performance is attributed to their unique morphology and surface structure. We believe that the synthetic strategy outlined here could be extended to other rationally designed monometallic or bimetallic nanoassemblies for use in high performance fuel cells.
基金the National Natural Science Foundation of China (21473111)the Fundamental Research Funds for the Central Universities (GK201701007)
文摘The research on electrocatalysts with relatively lower price than Pt and excellent electrocatalytic performance for the cathode oxygen reduction reaction(ORR) and anode methanol oxidation reaction(MOR) is vital for the development of direct methanol fuel cells(DMFCs). In this work, we develop a cyanogel-reduction method to synthesize reduced graphene oxide(rGO) supported highly dispersed PdNi alloy nanocrystals(PdNi/rGO) with high alloying degree and tunable Pd/Ni ratio. The large specific surface area and the d-band center downshift of Pd result in excellent activity of Pd4 Ni1/rGO nanohybrids for the ORR. The modification of Pd electronic structure can facilitate the adsorption of CH3 OH on Pd surface and the highly oxophilic property of Ni can eliminate/mitigate the COadsintermediates poisoning, which make PdNi/r GO nanohybrids possess superior MOR activity. In addition, rGO improve the stability of PdNi alloy nanocrystals for the ORR and MOR. Due to high activity and stability for the ORR and MOR, PdNi/rGO nanohybrids are promising to be an available bifunctional electrocatalyst in DMFCs.
基金financially supported by the National Natural Science Foundation of China (No. 22071140)the Natural Science Foundation of Shaanxi Province (No. 2021JLM-20)the Fundamental Research Funds for the Central Universities (No. GK202101002)。
文摘Acetylene (C_(2)H_(2)) and ethylene (C_(2)H_(4)) both are important chemical raw materials and energy fuel gasses.But the effective removement of trace C_(2)H_(2)from C_(2)H_(4)and the purification of C_(2)H_(2)from carbon dioxide(CO_(2)) are particularly challenging in the petrochemical industry.As a class of porous physical adsorbent,metal-organic frameworks (MOFs) have exhibited great success in separation and purification of light hydrocarbon gas.Herein,we rationally designed four novel MOFs by the strategy of pore space partition(PSP) via introducing triangular tri(pyridin-4-yl)-amine (TPA) into the 1D hexagonal channels of acs-type parent skeleton.By modulating the functional groups of linear dicarboxylate linkers for the parent skeleton,a series of isoreticular PSP-MOFs (SNNU-278-281) were successfully obtained.The synergistic effects of suitable pore size and Lewis basic functional groups make these MOFs ideal C_(2)H_(2)adsorbents.The gas adsorption experimental results show that all MOFs have excellent C_(2)H_(2)uptakes.Specially,SNNU-278demonstrates a high C_(2)H_(2)uptake of 149.7 cm3/g at 273 K and 1 atm.Meanwhile,SNNU-278-281 MOFs also show extremely great C_(2)H_(2)separation from CO_(2)and C_(2)H_(4).The optimized SNNU-281 with highdensity hydroxy groups exhibits extraordinary C_(2)H_(2)/CO_(2)and C_(2)H_(2)/C_(2)H_(4)dynamic breakthrough interval times up to 31 min/g and 17 min/g under 298 K and 1 bar.
