In the original version,Fig.5(f)is misused because it is identical to Fig.5(e).Figure 5 after correction is shown below:The authors apologize for any confusion.
Atomically dispersed Cu-based single-metal-site catalysts(Cu-N-C)have emerged as a frontier for electrocatalytic oxygen reduction reactions(ORR)because they can effectively optimize the D-band center of the Cu active ...Atomically dispersed Cu-based single-metal-site catalysts(Cu-N-C)have emerged as a frontier for electrocatalytic oxygen reduction reactions(ORR)because they can effectively optimize the D-band center of the Cu active site and provide appropriate adsorption/desorption energy for oxygen-containing intermediates.Metal-organic frameworks(MOFs)show excellent prospects in many fields because of their structural regularity and designability,but their direct use for electrocatalysis has been rarely reported due to the low intrinsic conductivity.Here,a MOF material(Cu-TCNQ)with highly regular single-atom copper active centers was successfully prepared using a solution chemical reaction method.Subsequently,Cu-TCNQ and graphene oxide(GO)were directly self-assembled to form a Cu-TCNQ/GO composite,which improved the conductivity of the catalyst while maintained the atomically precise controllability.The resistivity of the Cu-TCNQ/GO decreased by three orders of magnitude(1663.6-2.7 W/cm)compared with pure Cu-TCNQ.The half-wave potential was as high as 0.92 V in 0.1 mol/L KOH,even better than that of commercial 20%Pt/C.In alkaline polymer electrolyte fuel cells(APEFCs),the open-circuit voltage and power density of Cu-TCNQ/GO electrode reached 0.95 V and 320 m W/cm^(2),respectively,which suggests that Cu-TCNQ/GO has a good potential for application as a cathode ORR catalyst.展开更多
SnO_(2),with its high theoretical capacity,abundant resources,and environmental friendliness,is widely regarded as a potential anode material for lithium-ion batteries(LIBs).Nevertheless,the coarsening of the Sn nanop...SnO_(2),with its high theoretical capacity,abundant resources,and environmental friendliness,is widely regarded as a potential anode material for lithium-ion batteries(LIBs).Nevertheless,the coarsening of the Sn nanoparticles impedes the reconversion back to SnO_(2),resulting in low coulombic efficiency and rapid capacity decay.In this study,we fabricated a heterostructure by combining SnO_(2)nanoparticles with MoS_(2)nanosheets via plasma-assisted milling.The heterostructure consists of in-situ exfoliated MoS_(2)nanosheets predominantly in 1 T phase,which tightly encase the SnO_(2)nanoparticles through strong bonding.This configuration effectively mitigates the volume change and particle aggregation upon cycling.Moreover,the strong affinity of Mo,which is the lithiation product of MoS_(2),toward Sn plays a pivotal role in inhibiting the coarsening of Sn nanograins,thus enhancing the reversibility of Sn to SnO_(2)upon cycling.Consequently,the SnO_(2)/MoS_(2)heterostructure exhibits superb performance as an anode material for LIBs,demonstrating high capacity,rapid rate capability,and extended lifespan.Specifically,discharged/charged at a rate of 0.2 A g^(-1)for 300 cycles,it achieves a remarkable reversible capacity of 1173.4 mAh g^(-1).Even cycled at high rates of 1.0 and 5.0 A g^(-1)for 800 cycles,it still retains high reversible capacities of 1005.3 and 768.8 mAh g^(-1),respectively.Moreover,the heterostructure exhibits outstanding electrochemical performance in both full LIBs and sodium-ion batteries.展开更多
Electrocatalytic hydrogenation(ECH)offers a sustainable route for the conversion of biomass-derived feedstocks under ambient conditions;however,an atomic-level understanding of the catalytic mechanism based on heterog...Electrocatalytic hydrogenation(ECH)offers a sustainable route for the conversion of biomass-derived feedstocks under ambient conditions;however,an atomic-level understanding of the catalytic mechanism based on heterogeneous electrodes is lacking.To gain insights into the relation between electrocatalysis and the catalyst surface configuration,herein,the facet dependence of the ECH of furfural(FAL)is investigated on models of nanostructured Pd cubes,rhombic dodecahedrons,and octahedrons,which are predominantly enclosed by{100},{110},and{111}facets,respectively.The facet-dependent specific activity to afford furfuryl alcohol(FOL)follows the order of{111}>{100}>{110}.Experimental and theoretical kinetic analyses confirmed the occurrence of a competitive adsorption Langmuir-Hinshelwood mechanism on Pd,in which the ECH activity can be correlated with the difference between the binding energies of chemisorbed H(^(*)H)and FAL(^(*)FAL)based on density functional theoretical(DFT)calculations.Among the three facets,Pd{111}exhibiting the strongest^(*)H but the weakest^(*)FAL showed the copresence of the^(*)H and^(*)FAL intermediates on the Pd surface for subsequent hydrogenation,experimentally confirming its high ECH activity and Faradaic efficiency.The free energies determined using DFT calculations indicated that^(*)H addition to the carbonyl of FAL on Pd{111}was thermodynamically preferred over desorption to gaseous H2,contributing to efficient ECH to afford FOL at the expense of H2 evolution.The obtained insights into the facet-dependent ECH underline that surface bindings assist ECH or H2 evolution considering their competitiveness.These findings are expected to deepen the fundamental understanding of electrochemical refinery and broaden the scope of electrocatalyst exploration.展开更多
Cathodic electrocatalytic reactions, such as hydrogen evolution and CO_(2)/N_(2) reduction, are the key processes that store intermittent electricity into stable chemical energy. Although a great progress has been mad...Cathodic electrocatalytic reactions, such as hydrogen evolution and CO_(2)/N_(2) reduction, are the key processes that store intermittent electricity into stable chemical energy. Although a great progress has been made to boost activity and selectivity via elaborative catalyst design, the structure–property relationships have not been sufficiently understood in the context of surface reconfiguration under working conditions. Recent efforts devoted to tracking dynamic evolution of electrocatalysts using in-situ and/or operando techniques gave new insights into the real structure and working mechanism of active sites,and provided principles to design better catalysts. The achievement of cathodic electrocatalysts in this subject is herein summarized, focusing on the correlations between reconstructed surface and electrocatalytic performance. Briefly, the thermodynamics of reconstruction at cathodes is discussed at first, and then the representative progresses in H_(2) evolution and CO_(2)/N_(2) reduction are introduced in sequence to acquire insights into electrochemical processes on in-situ reconfigured surfaces or interfaces. Finally, a perspective is offered to guide future investigations. This review is anticipated to shed some new light on in-depth understanding cathodic electrocatalysis and exploiting prominent electrocatalysts.展开更多
Hydrogen has emerged as a promising environmentally friendly energy source. The development of lowcost, highly active, stable, and easily synthesized catalysts for hydrogen evolution reactions(HER) remains a significa...Hydrogen has emerged as a promising environmentally friendly energy source. The development of lowcost, highly active, stable, and easily synthesized catalysts for hydrogen evolution reactions(HER) remains a significant challenge. This study explored the synthesis of nitrogen-doped MXene-based composite catalysts for enhanced HER performance. By thermally decomposing RuCl_(3) coordinated with melamine and formaldehyde resin, we successfully introduced nitrogen-doped carbon(N–C) with highly dispersed ruthenium(Ru) onto the MXene surface. The calcination temperature played a crucial role in controlling the size of Ru nanoparticles(Ru NPs) and the proportion of Ru single-atom(Ru SA), thereby facilitating the synergistic enhancement of HER performance by Ru NPs and Ru SA. The resulting catalyst prepared with a calcination temperature of 600℃, Ti_(3)C_(2)T_x-N/C-Ru-600(TNCR-600), exhibited exceptional HER activity(η10= 17 m V) and stability(160 h) under alkaline conditions. This work presented a simple and effective strategy for synthesizing composite catalysts, offering new insights into the design and regulation of high-performance Ru-based catalysts for hydrogen production.展开更多
Flow dynamics of binary particles are investigated to realize the monitoring and optimization of fluidized beds.It is a challenge to accurately classify the mass fraction of mixed biomass,considering the limitations o...Flow dynamics of binary particles are investigated to realize the monitoring and optimization of fluidized beds.It is a challenge to accurately classify the mass fraction of mixed biomass,considering the limitations of existing techniques.The data collected from an electrostatic sensor array is analyzed.Cross correlation,empirical mode decomposition(EMD),Hilbert-Huang transform(HHT)are applied to process the signals.Under a higher mass fraction of the wood sawdust,the segregation behavior occurs,and the high energy region of HHT spectrum increases.Furthermore,two data-driven models are trained based on a hybrid wavelet scattering transform and bidirectional long short-term memory(ST-BiLSTM)network and a EMD and BiLSTM(EMD-BiLSTM)network to identify the mass fractions of the mixed biomass,with accuracies of 92%and 99%.The electrostatic sensing combined with the EMD-BiLSTM model is effective to classify the mass fraction of the mixed biomass.展开更多
Cost-efficient electrocatalysts composed of earth-abundant elements are highly desired for enhanced oxygen evolution reaction (OER).As a promising candidate,metallic Co4N already demonstrated electrocatalytic performa...Cost-efficient electrocatalysts composed of earth-abundant elements are highly desired for enhanced oxygen evolution reaction (OER).As a promising candidate,metallic Co4N already demonstrated electrocatalytic performance relying on specific nanostructures and electronic configurations.Herein,nickel was introduced as the dopant into one-dimensional (1D) hierarchical Co4N structures,achieving effective electronic regulation of Co4N toward high OER performance.The amount of Co3+increased after Ni-doping,and the in-situ formed surface oxyhydroxide during OER enhanced the electrocatalytic kinetics.Meanwhile,the 1D hierarchical structure further promoted the performances of Co4N owing to the high electrical conductivity and abundant activesites on the rough surface.As expected,the optimal Ni-doped Co4N with a Ni/Co molar ratio of 0.25 provides a small overpotential of 233 mV at a current density of 10 mA cm^(-2),with a low Tafel slope of 61 mV dec^(-1),and high long-term stability in 1.0 mol L^(-1)KOH.Following these results,the enhancement by doping the Co4N nanowire bundles with Fe and Cu was further evidenced for the OER.展开更多
Electrocatalytic hydrogenation(ECH)enables the sustainable production of chemicals under ambient condition;however,suffers from serious competition with hydrogen(H2)evolution and the use of precious metals as electroc...Electrocatalytic hydrogenation(ECH)enables the sustainable production of chemicals under ambient condition;however,suffers from serious competition with hydrogen(H2)evolution and the use of precious metals as electrocatalysts.Herein,molybdenum disulfide is for the first time developed as an efficient and noble-metal-free catalyst for ECH via in situ intercalation of ammonia or alkyl-amine cations.This interlayer engineering regulates phase transition(2H→1 T),and effectively ameliorates electronic configurations and surface hydrophobicity to promote the ECH of biomass-derived oxygenates,while prohibiting H2 evolution.The optimal one intercalated by dimethylamine(MoS_(2)-DMA)is capable of hydrogenating furfural(FAL)to furfuryl alcohol with high Faradaic efficiency of 86.3%–73.3%and outstanding selectivity of>95.0%at−0.25 to−0.65 V(vs.RHE),outperforming MoS_(2) and other conventional metals.Such prominent performance stems from the enhanced chemisorption and surface hydrophobicity.The chemisorption of H intermediate and FAL,synchronously strengthened on the edge-sites of MoS_(2)-DMA,accelerates the surface elementary step following Langmuir-Hinshelwood mechanism.Moreover,the improved hydrophobicity benefits FAL affinity to overcome diffusion limitation.Discovering the effective modulation of MoS_(2) from a typical H2 evolution electrocatalyst to a promising candidate for ECH,this study broadens the scope to exploit catalysts used for electrochemical synthesis.展开更多
Anode materials based on conversion reactions usually possess high energy densities for lithium-ion batteries(LIBs).However,they suffer from poor rate performance and cycle life due to serious volume changes.Herein,α...Anode materials based on conversion reactions usually possess high energy densities for lithium-ion batteries(LIBs).However,they suffer from poor rate performance and cycle life due to serious volume changes.Herein,α/β-CoMo04 heterogeneous nanorods are synthesized via a facile co-precipitation method,and further are phase-engineered through varying calcination temperature,accomplishing the obviously improved cycle life and rate performance as anodes for LIBs.When evaluated at a current density of 1.0 A·g^(-1)the optimal nanorods with anα/βphase ratio of 6.0 afford the reversible capacity of 1143.6 mAh·g^(-1)after 200 cycles,outperforming most of recently reported bimetal oxides.Li^(+)storage mechanism is further analyzed by using in-situ X-ray diffraction and ex-situ transition electronic microscopy.It's revealed thatβ-CoMoO_(4)follows a one-step conversion reaction;whileα-CoMo0_(4)proceeds an intercalation pathway before the conversion reaction.Grading storage of Li^(+)would alleviate the volume effect of heterostructuredα/β-CoMo0_(4),forming electronically conductive network evenly composed of Co and Mo nanograins to enable the reversible electrochemical conversion.This work is anticipated to give some hints for the rational design of high-performance energy materials.展开更多
It is still a challenge to prepare a water-and polymer-based electrospun air filter film with high efficiency filtration,low pressure drop,and good mechanical properties.To address this issue,polyvinyl alcohol(PVA)was...It is still a challenge to prepare a water-and polymer-based electrospun air filter film with high efficiency filtration,low pressure drop,and good mechanical properties.To address this issue,polyvinyl alcohol(PVA)was employed as the main material,mixing polyethyleneimine(PEI),bamboo-based activated carbon(BAC)and cellulose nanocrystal(CNC)to construct the air filter film by electrostatic electrospinning.In this system,the negatively charged BAC and CNC are fixed in the system through bonding with the positively charged PEI,showing a double adsorption effect.One is the mechanical filtration of the porous network structure constructed by PVA@PEI electrospun nanofibers,and the other is the electrostatic adsorption of PM2.5 on the surface of BAC and CNC.It is significant that the resulting composite air filter displays a high filtration efficiency of 95.86%,a pressure drop of only 59 Pa,and good thermal stability.Moreover,the introduced methyltrimethoxysilane(MTMS)endows it with good water-resistance.Given these excellent performances,this system can provide theoretical and technical references for the development of water-and polymerbased electrospun air filter film.展开更多
Biochar is a potential porous carbon to remove the contaminants from aquatic environments.Herein,N-doped hierarchical biochar was produced by the combined approach of ammonia torrefaction pretreatment(ATP)and alkali a...Biochar is a potential porous carbon to remove the contaminants from aquatic environments.Herein,N-doped hierarchical biochar was produced by the combined approach of ammonia torrefaction pretreatment(ATP)and alkali activation.ATP could not only incorporate N element into poplar wood,but obtain the loose structure of poplar wood.The highest surface area of N-doped hierarchical biochar was 2324.61 m^(2) g^(−1) after ammonia wet torrefaction pretreatment,which was higher than that of activation carbon(1401.82 m^(2) g^(−1))without torrefaction pretreatment,the hierarchical biochar(2111.03 m^(2) g^(−1))without ammonia atmosphere.The N-doped hierarchical biochar presented the highest adsorption capacity(564.7 mg g^(−1))of methyl orange(MO),which was 14.64-fold of that on biochar without N doping.In addition,the pseudo-second-order and Langmuir model fitted well with the adsorption kinetics and isotherms of the N-doped hierarchical biochar.The incorporation of nitrogen element could not only tune the distribution of surface electrons on biochar,but optimize the ambient condition of adsorption active sites as well.The adsorption of MO might occur on the N-/O-containing functional groups through the electrostatic interaction,theπ-πdispersion interaction,and the hydrogen bonding.The density functional theory showed that the graphitic-N and pyridinic-N were the dominant adsorption active sites.展开更多
In recent years,superhydrophobic coatings have received extensive attention due to their functions of waterproof,antifouling,self-cleaning,etc.However,wide applications of superhydrophobic coatings are still affected ...In recent years,superhydrophobic coatings have received extensive attention due to their functions of waterproof,antifouling,self-cleaning,etc.However,wide applications of superhydrophobic coatings are still affected by their disadvantages of complex preparation,low mechanical properties,and poor ultraviolet(UV)resistance.In this study,cellulose nanocrystal containing a small amount of lignin(L-CNC)/SiO_(2)composite particles were usedas the main material,polydimethylsiloxane(PDMS)as the adhesive and perfluorooctyltrichlorosilane(FOTS)as the modifier to prepare superhydrophobic coatings by a one-step spray method.The resulted coating showed excellent superhydrophobicity(water contact angle(WCA)of 161°and slide angle(SA)of 7)and high abrasion resistance(capable of withstanding 50 abrasion cycles under the load of 50 g).Moreover,it still maintained good superhydrophobicity after 5 h of exposure to the UV light(1000 W),displaying its good UV resistance.This study provides theoretical and technical referencefor thesimple preparationof organic-inorganic composite superhydrophobic coatings with high abrasion resistance and good UV resistance,which is beneficial to improving the practicability and broadening the application scope of superhydrophobic coatings.展开更多
文摘In the original version,Fig.5(f)is misused because it is identical to Fig.5(e).Figure 5 after correction is shown below:The authors apologize for any confusion.
基金supported by the National Key Research and Development Program of China(No.2022YFB3807500)the National Natural Science Foundation of China(No.22220102003)+1 种基金the Beijing Natural Science Foundation(No.JL23003)“Double-First-Class”construction projects(Nos.XK180301 and XK1804-02)。
文摘Atomically dispersed Cu-based single-metal-site catalysts(Cu-N-C)have emerged as a frontier for electrocatalytic oxygen reduction reactions(ORR)because they can effectively optimize the D-band center of the Cu active site and provide appropriate adsorption/desorption energy for oxygen-containing intermediates.Metal-organic frameworks(MOFs)show excellent prospects in many fields because of their structural regularity and designability,but their direct use for electrocatalysis has been rarely reported due to the low intrinsic conductivity.Here,a MOF material(Cu-TCNQ)with highly regular single-atom copper active centers was successfully prepared using a solution chemical reaction method.Subsequently,Cu-TCNQ and graphene oxide(GO)were directly self-assembled to form a Cu-TCNQ/GO composite,which improved the conductivity of the catalyst while maintained the atomically precise controllability.The resistivity of the Cu-TCNQ/GO decreased by three orders of magnitude(1663.6-2.7 W/cm)compared with pure Cu-TCNQ.The half-wave potential was as high as 0.92 V in 0.1 mol/L KOH,even better than that of commercial 20%Pt/C.In alkaline polymer electrolyte fuel cells(APEFCs),the open-circuit voltage and power density of Cu-TCNQ/GO electrode reached 0.95 V and 320 m W/cm^(2),respectively,which suggests that Cu-TCNQ/GO has a good potential for application as a cathode ORR catalyst.
基金the financial support from the National Key Research and Development Program of China(2018YFA0209402,2022YFB2502003)Guangdong Basic and Applied Basic Research Foundation(2023B1515040011)Jiangxi Provincial Natural Science Foundation(20212BAB214028)
文摘SnO_(2),with its high theoretical capacity,abundant resources,and environmental friendliness,is widely regarded as a potential anode material for lithium-ion batteries(LIBs).Nevertheless,the coarsening of the Sn nanoparticles impedes the reconversion back to SnO_(2),resulting in low coulombic efficiency and rapid capacity decay.In this study,we fabricated a heterostructure by combining SnO_(2)nanoparticles with MoS_(2)nanosheets via plasma-assisted milling.The heterostructure consists of in-situ exfoliated MoS_(2)nanosheets predominantly in 1 T phase,which tightly encase the SnO_(2)nanoparticles through strong bonding.This configuration effectively mitigates the volume change and particle aggregation upon cycling.Moreover,the strong affinity of Mo,which is the lithiation product of MoS_(2),toward Sn plays a pivotal role in inhibiting the coarsening of Sn nanograins,thus enhancing the reversibility of Sn to SnO_(2)upon cycling.Consequently,the SnO_(2)/MoS_(2)heterostructure exhibits superb performance as an anode material for LIBs,demonstrating high capacity,rapid rate capability,and extended lifespan.Specifically,discharged/charged at a rate of 0.2 A g^(-1)for 300 cycles,it achieves a remarkable reversible capacity of 1173.4 mAh g^(-1).Even cycled at high rates of 1.0 and 5.0 A g^(-1)for 800 cycles,it still retains high reversible capacities of 1005.3 and 768.8 mAh g^(-1),respectively.Moreover,the heterostructure exhibits outstanding electrochemical performance in both full LIBs and sodium-ion batteries.
文摘Electrocatalytic hydrogenation(ECH)offers a sustainable route for the conversion of biomass-derived feedstocks under ambient conditions;however,an atomic-level understanding of the catalytic mechanism based on heterogeneous electrodes is lacking.To gain insights into the relation between electrocatalysis and the catalyst surface configuration,herein,the facet dependence of the ECH of furfural(FAL)is investigated on models of nanostructured Pd cubes,rhombic dodecahedrons,and octahedrons,which are predominantly enclosed by{100},{110},and{111}facets,respectively.The facet-dependent specific activity to afford furfuryl alcohol(FOL)follows the order of{111}>{100}>{110}.Experimental and theoretical kinetic analyses confirmed the occurrence of a competitive adsorption Langmuir-Hinshelwood mechanism on Pd,in which the ECH activity can be correlated with the difference between the binding energies of chemisorbed H(^(*)H)and FAL(^(*)FAL)based on density functional theoretical(DFT)calculations.Among the three facets,Pd{111}exhibiting the strongest^(*)H but the weakest^(*)FAL showed the copresence of the^(*)H and^(*)FAL intermediates on the Pd surface for subsequent hydrogenation,experimentally confirming its high ECH activity and Faradaic efficiency.The free energies determined using DFT calculations indicated that^(*)H addition to the carbonyl of FAL on Pd{111}was thermodynamically preferred over desorption to gaseous H2,contributing to efficient ECH to afford FOL at the expense of H2 evolution.The obtained insights into the facet-dependent ECH underline that surface bindings assist ECH or H2 evolution considering their competitiveness.These findings are expected to deepen the fundamental understanding of electrochemical refinery and broaden the scope of electrocatalyst exploration.
基金the financial support from the National Major Research and Development Plan(2018YFA0209402)the National Natural Science Foundation of China(22175077,21773093,22088101)the Natural Science Foundation of Guangdong Province(2021A1515012351)。
文摘Cathodic electrocatalytic reactions, such as hydrogen evolution and CO_(2)/N_(2) reduction, are the key processes that store intermittent electricity into stable chemical energy. Although a great progress has been made to boost activity and selectivity via elaborative catalyst design, the structure–property relationships have not been sufficiently understood in the context of surface reconfiguration under working conditions. Recent efforts devoted to tracking dynamic evolution of electrocatalysts using in-situ and/or operando techniques gave new insights into the real structure and working mechanism of active sites,and provided principles to design better catalysts. The achievement of cathodic electrocatalysts in this subject is herein summarized, focusing on the correlations between reconstructed surface and electrocatalytic performance. Briefly, the thermodynamics of reconstruction at cathodes is discussed at first, and then the representative progresses in H_(2) evolution and CO_(2)/N_(2) reduction are introduced in sequence to acquire insights into electrochemical processes on in-situ reconfigured surfaces or interfaces. Finally, a perspective is offered to guide future investigations. This review is anticipated to shed some new light on in-depth understanding cathodic electrocatalysis and exploiting prominent electrocatalysts.
基金financially supported by the National Key R&D Program of China (No.2018YFA0209402)the National Natural Science Foundation of China (Nos.22088101, 22175132, 22072028)。
文摘Hydrogen has emerged as a promising environmentally friendly energy source. The development of lowcost, highly active, stable, and easily synthesized catalysts for hydrogen evolution reactions(HER) remains a significant challenge. This study explored the synthesis of nitrogen-doped MXene-based composite catalysts for enhanced HER performance. By thermally decomposing RuCl_(3) coordinated with melamine and formaldehyde resin, we successfully introduced nitrogen-doped carbon(N–C) with highly dispersed ruthenium(Ru) onto the MXene surface. The calcination temperature played a crucial role in controlling the size of Ru nanoparticles(Ru NPs) and the proportion of Ru single-atom(Ru SA), thereby facilitating the synergistic enhancement of HER performance by Ru NPs and Ru SA. The resulting catalyst prepared with a calcination temperature of 600℃, Ti_(3)C_(2)T_x-N/C-Ru-600(TNCR-600), exhibited exceptional HER activity(η10= 17 m V) and stability(160 h) under alkaline conditions. This work presented a simple and effective strategy for synthesizing composite catalysts, offering new insights into the design and regulation of high-performance Ru-based catalysts for hydrogen production.
基金the National Natural Science Foundation of China (grant No.62303022)for its funding.
文摘Flow dynamics of binary particles are investigated to realize the monitoring and optimization of fluidized beds.It is a challenge to accurately classify the mass fraction of mixed biomass,considering the limitations of existing techniques.The data collected from an electrostatic sensor array is analyzed.Cross correlation,empirical mode decomposition(EMD),Hilbert-Huang transform(HHT)are applied to process the signals.Under a higher mass fraction of the wood sawdust,the segregation behavior occurs,and the high energy region of HHT spectrum increases.Furthermore,two data-driven models are trained based on a hybrid wavelet scattering transform and bidirectional long short-term memory(ST-BiLSTM)network and a EMD and BiLSTM(EMD-BiLSTM)network to identify the mass fractions of the mixed biomass,with accuracies of 92%and 99%.The electrostatic sensing combined with the EMD-BiLSTM model is effective to classify the mass fraction of the mixed biomass.
基金financial support from China Postdoctoral Science Foundation (2020M673056)the National Key Research and Development Program of China (2018YFA0209402)the National Natural Science Foundation of China (21773093)。
文摘Cost-efficient electrocatalysts composed of earth-abundant elements are highly desired for enhanced oxygen evolution reaction (OER).As a promising candidate,metallic Co4N already demonstrated electrocatalytic performance relying on specific nanostructures and electronic configurations.Herein,nickel was introduced as the dopant into one-dimensional (1D) hierarchical Co4N structures,achieving effective electronic regulation of Co4N toward high OER performance.The amount of Co3+increased after Ni-doping,and the in-situ formed surface oxyhydroxide during OER enhanced the electrocatalytic kinetics.Meanwhile,the 1D hierarchical structure further promoted the performances of Co4N owing to the high electrical conductivity and abundant activesites on the rough surface.As expected,the optimal Ni-doped Co4N with a Ni/Co molar ratio of 0.25 provides a small overpotential of 233 mV at a current density of 10 mA cm^(-2),with a low Tafel slope of 61 mV dec^(-1),and high long-term stability in 1.0 mol L^(-1)KOH.Following these results,the enhancement by doping the Co4N nanowire bundles with Fe and Cu was further evidenced for the OER.
基金supported by the National Key Research and Development Program of China (2018YFA0209402)the National Natural Science Foundation of China (21773093)
文摘Electrocatalytic hydrogenation(ECH)enables the sustainable production of chemicals under ambient condition;however,suffers from serious competition with hydrogen(H2)evolution and the use of precious metals as electrocatalysts.Herein,molybdenum disulfide is for the first time developed as an efficient and noble-metal-free catalyst for ECH via in situ intercalation of ammonia or alkyl-amine cations.This interlayer engineering regulates phase transition(2H→1 T),and effectively ameliorates electronic configurations and surface hydrophobicity to promote the ECH of biomass-derived oxygenates,while prohibiting H2 evolution.The optimal one intercalated by dimethylamine(MoS_(2)-DMA)is capable of hydrogenating furfural(FAL)to furfuryl alcohol with high Faradaic efficiency of 86.3%–73.3%and outstanding selectivity of>95.0%at−0.25 to−0.65 V(vs.RHE),outperforming MoS_(2) and other conventional metals.Such prominent performance stems from the enhanced chemisorption and surface hydrophobicity.The chemisorption of H intermediate and FAL,synchronously strengthened on the edge-sites of MoS_(2)-DMA,accelerates the surface elementary step following Langmuir-Hinshelwood mechanism.Moreover,the improved hydrophobicity benefits FAL affinity to overcome diffusion limitation.Discovering the effective modulation of MoS_(2) from a typical H2 evolution electrocatalyst to a promising candidate for ECH,this study broadens the scope to exploit catalysts used for electrochemical synthesis.
基金the National Natural Science Foundation of China(Nos.21773093 and 51671089)the Natural Science Foundation of Guangdong Province(No.2017B030306004)the Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme,and the Open Fund of the Guangdong Provincial Key Laboratory of Advanced Energy Storage Materials(No.AESM201701).
文摘Anode materials based on conversion reactions usually possess high energy densities for lithium-ion batteries(LIBs).However,they suffer from poor rate performance and cycle life due to serious volume changes.Herein,α/β-CoMo04 heterogeneous nanorods are synthesized via a facile co-precipitation method,and further are phase-engineered through varying calcination temperature,accomplishing the obviously improved cycle life and rate performance as anodes for LIBs.When evaluated at a current density of 1.0 A·g^(-1)the optimal nanorods with anα/βphase ratio of 6.0 afford the reversible capacity of 1143.6 mAh·g^(-1)after 200 cycles,outperforming most of recently reported bimetal oxides.Li^(+)storage mechanism is further analyzed by using in-situ X-ray diffraction and ex-situ transition electronic microscopy.It's revealed thatβ-CoMoO_(4)follows a one-step conversion reaction;whileα-CoMo0_(4)proceeds an intercalation pathway before the conversion reaction.Grading storage of Li^(+)would alleviate the volume effect of heterostructuredα/β-CoMo0_(4),forming electronically conductive network evenly composed of Co and Mo nanograins to enable the reversible electrochemical conversion.This work is anticipated to give some hints for the rational design of high-performance energy materials.
基金the China Postdoctoral Science Foundation(No.2021M692806)the Natural Science Foundation of Zhejiang Province(No.LY21C160002)the Scientific Research Development Foundation of Zhejiang A&F University(No.2018FR054).
文摘It is still a challenge to prepare a water-and polymer-based electrospun air filter film with high efficiency filtration,low pressure drop,and good mechanical properties.To address this issue,polyvinyl alcohol(PVA)was employed as the main material,mixing polyethyleneimine(PEI),bamboo-based activated carbon(BAC)and cellulose nanocrystal(CNC)to construct the air filter film by electrostatic electrospinning.In this system,the negatively charged BAC and CNC are fixed in the system through bonding with the positively charged PEI,showing a double adsorption effect.One is the mechanical filtration of the porous network structure constructed by PVA@PEI electrospun nanofibers,and the other is the electrostatic adsorption of PM2.5 on the surface of BAC and CNC.It is significant that the resulting composite air filter displays a high filtration efficiency of 95.86%,a pressure drop of only 59 Pa,and good thermal stability.Moreover,the introduced methyltrimethoxysilane(MTMS)endows it with good water-resistance.Given these excellent performances,this system can provide theoretical and technical references for the development of water-and polymerbased electrospun air filter film.
基金Key R&D Program of Zhejiang Province(2022C03092)Fundamental Research Funds for the Provincial Universities of Zhejiang(2020YQ006)+2 种基金Natural Science Foundation of Zhejiang Province(LY21E060001)Youth Talent Support Program by National Forestry and Grassland Administration(2019132617)Research Foundation of Talented Scholars of Zhejiang A&F University(2022LFR073)。
文摘Biochar is a potential porous carbon to remove the contaminants from aquatic environments.Herein,N-doped hierarchical biochar was produced by the combined approach of ammonia torrefaction pretreatment(ATP)and alkali activation.ATP could not only incorporate N element into poplar wood,but obtain the loose structure of poplar wood.The highest surface area of N-doped hierarchical biochar was 2324.61 m^(2) g^(−1) after ammonia wet torrefaction pretreatment,which was higher than that of activation carbon(1401.82 m^(2) g^(−1))without torrefaction pretreatment,the hierarchical biochar(2111.03 m^(2) g^(−1))without ammonia atmosphere.The N-doped hierarchical biochar presented the highest adsorption capacity(564.7 mg g^(−1))of methyl orange(MO),which was 14.64-fold of that on biochar without N doping.In addition,the pseudo-second-order and Langmuir model fitted well with the adsorption kinetics and isotherms of the N-doped hierarchical biochar.The incorporation of nitrogen element could not only tune the distribution of surface electrons on biochar,but optimize the ambient condition of adsorption active sites as well.The adsorption of MO might occur on the N-/O-containing functional groups through the electrostatic interaction,theπ-πdispersion interaction,and the hydrogen bonding.The density functional theory showed that the graphitic-N and pyridinic-N were the dominant adsorption active sites.
基金supported by the National Natural Science Foundation of China(Grant No.31901246)the Natural Science Foundation of Zhejiang Province(Grant No.LY21C160002)the Scientific Research Development Foundation of Zhejiang A&F University(Grant No.2021KX0042).
文摘In recent years,superhydrophobic coatings have received extensive attention due to their functions of waterproof,antifouling,self-cleaning,etc.However,wide applications of superhydrophobic coatings are still affected by their disadvantages of complex preparation,low mechanical properties,and poor ultraviolet(UV)resistance.In this study,cellulose nanocrystal containing a small amount of lignin(L-CNC)/SiO_(2)composite particles were usedas the main material,polydimethylsiloxane(PDMS)as the adhesive and perfluorooctyltrichlorosilane(FOTS)as the modifier to prepare superhydrophobic coatings by a one-step spray method.The resulted coating showed excellent superhydrophobicity(water contact angle(WCA)of 161°and slide angle(SA)of 7)and high abrasion resistance(capable of withstanding 50 abrasion cycles under the load of 50 g).Moreover,it still maintained good superhydrophobicity after 5 h of exposure to the UV light(1000 W),displaying its good UV resistance.This study provides theoretical and technical referencefor thesimple preparationof organic-inorganic composite superhydrophobic coatings with high abrasion resistance and good UV resistance,which is beneficial to improving the practicability and broadening the application scope of superhydrophobic coatings.
