The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct ...The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct activity-stability trade-off model is full of significance but challenging.Herein,a single atom Zn stabilized RuO_(2)with enriched oxygen vacancies(SA Zn-RuO_(2))is developed as a promising alternative to iridium oxide for acidic oxygen evolution reaction(OER).Compared with commercial RuO_(2),the enhanced Ru–O bond strength of SA Zn-RuO_(2)by forming Zn-O-Ru local structure motif is favorable to stabilize surface Ru,while the electrons transferred from Zn single atoms to adjacent Ru atoms protects the Ru active sites from overoxidation.Simultaneously,the optimized surrounding electronic structure of Ru sites in SA ZnRuO_(2)decreases the adsorption energies of OER intermediates to reduce the reaction barrier.As a result,the representative SA Zn-RuO_(2)exhibits a low overpotential of 210 mV to achieve 10 mA cm^(-2)and a greatly enhanced durability than commercial RuO_(2).This work provides a promising dual-engineering strategy by coupling single atom doping and vacancy for the tradeoff of high activity and catalytic stability toward acidic OER.展开更多
Herein,the impact of the independent control of processing additives on vertical phase separation in sequentially deposited (SD) organic photovoltaics (OPVs) and its subsequent effects on charge carrier kinetics at th...Herein,the impact of the independent control of processing additives on vertical phase separation in sequentially deposited (SD) organic photovoltaics (OPVs) and its subsequent effects on charge carrier kinetics at the electron donor-acceptor interface are investigated.The film morphology exhibits notable variations,significantly depending on the layer to which 1,8-diiodooctane (DIO) was applied.Grazing incidence wide-angle X-ray scattering analysis reveals distinctly separated donor/acceptor phases and vertical crystallinity details in SD films.Time-of-flight secondary ion mass spectrometry analysis is employed to obtain component distributions in diverse vertical phase structures of SD films depending on additive control.In addition,nanosecond transient absorption spectroscopy shows that DIO control significantly affects the dynamics of separated charges in SD films.In SD OPVs,DIO appears to act through distinct mechanisms with minimal restriction,depending on the applied layer.This study emphasizes the significance of morphological optimization in improving device performance and underscores the importance of independent additive control in the advancement of OPV technology.展开更多
Atomically‐dispersed copper sites coordinated with nitrogen‐doped carbon(Cu–N–C)can provide novel possibilities to enable highly selective and active electrochemical CO_(2) reduction reactions.However,the construc...Atomically‐dispersed copper sites coordinated with nitrogen‐doped carbon(Cu–N–C)can provide novel possibilities to enable highly selective and active electrochemical CO_(2) reduction reactions.However,the construction of optimal local electronic structures for nitrogen‐coordinated Cu sites(Cu–N_(4))on carbon remains challenging.Here,we synthesized the Cu–N–C catalysts with atomically‐dispersed edge‐hosted Cu–N_(4) sites(Cu–N_(4)C_(8))located in a micropore between two graphitic sheets via a facile method to control the concentration of metal precursor.Edge‐hosted Cu–N_(4)C_(8) catalysts outperformed the previously reported M–N–C catalysts for CO_(2)‐to‐CO conversion,achieving a maximum CO Faradaic efficiency(FECO)of 96%,a CO current density of–8.97 mA cm^(–2) at–0.8 V versus reversible hydrogen electrode(RHE),and over FECO of 90%from–0.6 to–1.0 V versus RHE.Computational studies revealed that the micropore of the graphitic layer in edge‐hosted Cu–N_(4)C_(8) sites causes the d‐orbital energy level of the Cu atom to shift upward,which in return decreases the occupancy of antibonding states in the*COOH binding.This research suggests new insights into tailoring the locally coordinated structure of the electrocatalyst at the atomic scale to achieve highly selective electrocatalytic reactions.展开更多
Electrocatalytic CO_(2)-to-formate conversion is considered an economically viable process.In general,Zn-based nanomaterials are well-known to be highly efficient electrocatalysts for the conversion of CO_(2) to CO,bu...Electrocatalytic CO_(2)-to-formate conversion is considered an economically viable process.In general,Zn-based nanomaterials are well-known to be highly efficient electrocatalysts for the conversion of CO_(2) to CO,but seldom do they exhibit excellent selectivity toward formate.In this article,we demonstrate that a heterointerface catalyst ZnO/ZnSnO3 with nanosheet morphology shows enhanced selectivity with a maximum Faradaic efficiency(FE)of 86%at−0.9 V versus reversible hydrogen electrode and larger current density for the conversion of CO_(2) to formate than pristine ZnO and ZnSnO3.In particular,the FEs of the C1 products(CO+HCOO−)exceed 98%over the potential window.The experimental measurements combined with theoretical calculations revealed that the ZnO in ZnO/ZnSnO3 heterojunction delivers the valence electron depletion and accordingly optimizes Zn d-band center,which results in moderate Zn-O hybridization of HCOO*and weakened Zn-C hybridization of competing COOH*,thus greatly boosting the HCOOH generation.Our study highlights the importance of charge redistribution in catalysts on the selectivity of electrochemical CO_(2) reduction.展开更多
Utilizing sunlight to convert CO_(2) into chemical fuels could address the greenhouse effect and fossil fuel crisis,Heterojunction structure catalysts with oxygen vacancy are attractive in the field of photocatalytic ...Utilizing sunlight to convert CO_(2) into chemical fuels could address the greenhouse effect and fossil fuel crisis,Heterojunction structure catalysts with oxygen vacancy are attractive in the field of photocatalytic CO_(2) conversion.Herein,a modified TiO_(2)/In_(2)O_(3)(R-P2 5/In_(2)O_(3-x)) type Ⅱ heterojunction composite with oxygen vacancies is designed for photocatalytic CO_(2) reduction,which exhibits excellent CO_(2) reduction activity,with a C_(2) selectivity of 56.66%(in terms of R_(electron)).In situ Fourier-transform infrared spectroscopy(DRIFTS) and time-resolved photoluminescence(TR-PL) spectroscopy are used to reveal the intermediate formation of the photocatalytic mechanism and photogenerated electron lifetime,respectively.The experimental characterizations reveal that the R-P25/In_(2)O_(3-x) composite shows a remarkable behavior for coupling C-C bonds.Besides,efficient charge separation contributes to the improved CO_(2) conversion performance of photocatalysts.This work introduces a type Ⅱ heterojunction composite photocatalyst,which promotes understanding the CO_(2) reduction mechanisms on heterojunction composites and is valuable for the development of photocatalysts.展开更多
The layeredδ-MnO_(2)(dMO)is an excellent cathode material for rechargeable aqueous zinc-ion batteries owing to its large interlayer distance(~0.7 nm),high capacity,and low cost;however,such cathodes suffer from struc...The layeredδ-MnO_(2)(dMO)is an excellent cathode material for rechargeable aqueous zinc-ion batteries owing to its large interlayer distance(~0.7 nm),high capacity,and low cost;however,such cathodes suffer from structural degradation during the long-term cycling process,leading to capacity fading.In this study,a Co-doped dMO composite with reduced graphene oxide(GC-dMO)is developed using a simple cost-effective hydrothermal method.The degree of disorderness increases owing to the hetero-atom doping and graphene oxide composites.It is demonstrated that layered dMO and GC-dMO undergo a structural transition from K-birnessite to the Zn-buserite phase upon the first discharge,which enhances the intercalation of Zn^(2+)ions,H_(2)O molecules in the layered structure.The GC-dMO cathode exhibits an excellent capacity of 302 mAh g^(-1)at a current density of 100 mAg^(-1)after 100 cycles as compared with the dMO cathode(159 mAhg^(-1)).The excellent electrochemical performance of the GC-dMO cathode owing to Co-doping and graphene oxide sheets enhances the interlayer gap and disorderness,and maintains structural stability,which facilitates the easy reverse intercalation and de-intercalation of Zn^(2+)ions and H_(2)O molecules.Therefore,GC-dMO is a promising cathode material for large-scale aqueous ZIBs.展开更多
Pt-Ni alloy nanocrystals with Pt-enriched shells were prepared by selective etching of surface Ni using sulfuric acid and hydroquinone.The changes in the electronic and geometric structure of the alloy nanoparticles a...Pt-Ni alloy nanocrystals with Pt-enriched shells were prepared by selective etching of surface Ni using sulfuric acid and hydroquinone.The changes in the electronic and geometric structure of the alloy nanoparticles at the surface were elucidated from the electrochemical surface area,the potential of zero total charge(PZTC),and relative surface roughness,which were determined from CO-and CO_(2)-displacement experiments before and after 3000 potential cycles under oxygen reduction reaction conditions.While the highest activity and durability were achieved in hydroquinone-treated Pt–Ni,sulfuric acidtreated one showed the lower activity and durability despite its higher surface Pt concentration and alloying level.Both PZTC and QCO_(2)/QCO ratio(desorption charge of reductively adsorbed CO_(2) normalized by COad-stripping charge)depend on surface roughness.In particular,QCO_(2)/QCO ratio change better reflects the roughness on an atomic scale,and PZTC is also affected by the electronic modification of Pt atoms in surface layers.In this study,a comparative study is presented to find a relationship between surface structure and electrochemical properties,which reveals that surface roughness plays a critical role to improve the electrochemical performance of Pt-Ni alloy catalysts with Pt-rich surfaces.展开更多
Electrochemical N_(2) reduction reaction(eNRR) over Cu-based catalysts suffers from an intrinsically low activity of Cu for activation of stable N_(2) molecules and the limited supply of N_(2) to the catalyst due to i...Electrochemical N_(2) reduction reaction(eNRR) over Cu-based catalysts suffers from an intrinsically low activity of Cu for activation of stable N_(2) molecules and the limited supply of N_(2) to the catalyst due to its low solubility in aqueous electrolytes.Herein,we propose phosphorus-activated Cu electrocatalysts to generate electron-deficient Cu sites on the catalyst surface to promote the adsorption of N_(2) molecules.The eNRR system is further modified using a gas diffusion electrode(GDE) coated with polytetrafluoroethylene(PTFE) to form an effective three-phase boundary of liquid water-gas N_(2)-solid catalyst to facilitate easy access of N_(2) to the catalytic sites.As a result,the new catalyst in the flow-type cell records a Faradaic efficiency of 13.15% and an NH_(3) production rate of 7.69 μg h^(-1) cm^(-2) at-0.2 V_(RHE),which represent 3.56 and 59.2 times increases from those obtained with a pristine Cu electrode in a typical electrolytic cell.This work represents a successful demonstration of dual modification strategies;catalyst modification and N_(2) supplying system engineering,and the results would provide a useful platform for further developments of electrocatalysts and reaction systems.展开更多
For high-efficiency NH_(3)synthesis via ambient-condition electrohydrogenation of inert N_(2),it is pivotal to ingeniously design an active electrocatalyst with multiple features of abundant surfacial deficiency,good ...For high-efficiency NH_(3)synthesis via ambient-condition electrohydrogenation of inert N_(2),it is pivotal to ingeniously design an active electrocatalyst with multiple features of abundant surfacial deficiency,good conductivity and large surface area.Here,oxygen-deficient SnO_(2)nanoparticles encapsulated by ultrathin carbon layer(d-SnO_(2)@C)are developed by hydrothermal deposition coupled with annealing process,as promising catalysts for ambient electrocatalytic N_(2)reduction.d-SnO_(2)@C exhibits high activity and excellent selectivity for electrocatalytic conversion of N_(2)to NH_(3)in acidic electrolytes,with Faradic efficiency as high as 12.7%at-0.15 V versus the reversible hydrogen electrode(RHE)and large NH_(3)yield rate of 16.68μg h^(-1)mgcat^(-1)at-0.25 V vs.RHE in 0.1 mol L^(-1)HCl.Benefiting from the structural superiority of enhanced charge transfer efficiency and optimized surface states,d-SnO_(2)@C also achieves excellent long-term stability.展开更多
Herein, a stable and efficient CoS_(2)-ReS_(2) electrocatalyst is successfully constructed by using the different molar ratios of CoS_(2) on ReS_(2). The size and morphology of the catalysts are significantly changed ...Herein, a stable and efficient CoS_(2)-ReS_(2) electrocatalyst is successfully constructed by using the different molar ratios of CoS_(2) on ReS_(2). The size and morphology of the catalysts are significantly changed after the CoS_(2) is grown on ReS_(2), providing regulation of the catalytic activity of ReS_(2). Particularly, the optimized CoS_(2)-ReS_(2) shows superior electrocatalytic properties with a low voltage of 1.48 V at 20 mA cm^(-2) for overall water splitting in 1.0 M KOH, which is smaller than the noble metal-based catalysts(1.77 V at 20 mA cm^(-2)). The XPS, XAS, and theoretical data confirm that the interfacial regulation of ReS_(2) by CoS_(2) can provide rich edge catalytic sites, which greatly optimizes the catalytic kinetics and drop the energy barrier for oxygen/hydrogen evolution reactions. Our results demonstrated that interfacial engineering is an efficient route for fabricating high-performance water splitting electrocatalysts.展开更多
Iron sulfides have bee n con sidered as one of the most promising can didates for sodium ion battery anode materials due to their high theoretical capacity and low cost. I n this work, spin dle-like Fe7S8 with n itrog...Iron sulfides have bee n con sidered as one of the most promising can didates for sodium ion battery anode materials due to their high theoretical capacity and low cost. I n this work, spin dle-like Fe7S8 with n itroge rvdoped carb on (FeiS/N-C) nano hybrids are successfully syn thesized via a solvothermal method by sulfidation iron-based metal organic framework (FeMOF). As sodium ion battery an odes, FeySs/N-C nano hybrids exhibit high reversible capacity of 450.8 mAh g-1 at 200 mA·g^-1, and 406.7 mAh·g^-1 at 500 mA·g^-1 even after 500 cycles. They also show excellent rate properties and delivering the capacity of 327.8 mAh·g^-1 at a very high current density of 3.2 A·g^-1. These outstanding electrochemical performa nces can be attributed to the unique structure of Fe7S8/ N-C nan ohybrids. The nano scale dime nsion in their size can be ben eficial for facile ion and electro n tran sports. Furthermore, the stable n itroge n doped carb on frameworks can also improve electrical conductivity and relieve the problems related to volume expansion. X-ray absorption spectroscopy and X-ray photoelectron spectroscopy analyses have been performed to study reactions occurred in spindle-like FeySs/N-C nanohybrid electrode at both bulk and surface.展开更多
High energy ball-milled iron sulfides with thin carb on layer coati ng(BM-FeS/C composites)were prepared by the simple and econo mical process.Ball-milled process,followed by carb on coati ng,reduced the particle size...High energy ball-milled iron sulfides with thin carb on layer coati ng(BM-FeS/C composites)were prepared by the simple and econo mical process.Ball-milled process,followed by carb on coati ng,reduced the particle size and increased the electrical con ductivity.Whe n employed as sodium-ion battery ano des,BM?F eS/C composites showed extremely high electrochemical performa nee with reversible specific capacity of 589.8 mAh·g^-1 after 100 cycles at a current density of 100 mA·g^-1.They also exhibited superior rate capabilities of 375.9 mAh·g^-1 even at 3.2 Ag^1 and 423.6 mAh·g^-1 at 1.5 Ag_1.X-ray absorptio n near edge structure an alysis con firmed the electrochemical pathway for con version reaction of BM-FeS/C composites.展开更多
Electronic coupling with the support plays a crucial role in boosting the intrinsic catalytic activity of a single-atom catalyst.Herein,the three-dimensional(3D)hierarchical Co(OH)F nanosheet arrays modified by single...Electronic coupling with the support plays a crucial role in boosting the intrinsic catalytic activity of a single-atom catalyst.Herein,the three-dimensional(3D)hierarchical Co(OH)F nanosheet arrays modified by singleatom Ru(SA-Ru/Co(OH)F)are prepared by a facile one-step hydrothermal method under mild conditions,which exhibit excellent activity with an overpotential of 200 and 326 mV at 10 and 500 mA cm^(−2),respectively,as well as robust stability for oxygen evolution reaction(OER)in 1.0 mol L^(−1)KOH electrolyte.The study of electronic structures and surface chemical states before and after OER testing reveals that the strong electronic coupling between single-atom Ru and Co(OH)F induces the charge redistribution in SA-Ru/Co(OH)F and suppresses the excessive oxidation of Ru into higher valence state(more than+4)under high OER potential.This work provides a strategy to stabilize single-atom Ru by Co(OH)F that can enhance the activity and durability for OER under large current densities.展开更多
表面应力耦合异质结构是一种改善非均相催化剂催化性能的有效策略.它可以在调控催化剂电子结构的同时,促进电荷传输.一般来说,Bi基催化剂对CO_(2)电还原为甲酸的选择性高于ZnO,但是金属Bi的价格高于Zn.本文以十六烷基三甲基溴化铵为模板...表面应力耦合异质结构是一种改善非均相催化剂催化性能的有效策略.它可以在调控催化剂电子结构的同时,促进电荷传输.一般来说,Bi基催化剂对CO_(2)电还原为甲酸的选择性高于ZnO,但是金属Bi的价格高于Zn.本文以十六烷基三甲基溴化铵为模板剂,通过一步水热法合成了一种具有多孔纳米片形貌的Bi_(2)O_(2)CO_(3)/ZnO异质结催化剂,用于高效电催化CO_(2)还原制备甲酸.在-1.0 V vs.RHE下,该催化剂展现出最大甲酸盐法拉第效率(92%),且在施加-1.2 V vs.RHE电压下甲酸盐偏电流密度为200 m A mg_(Bi)^(-1).更重要的是,对Bi的质量进行归一化发现,Bi_(2)O_(2)CO_(3)/ZnO的质量活度比纯Bi_(2)O_(2)CO_(3)的质量活度提升了3.1倍.通过X-射线光电子能谱和X-射线吸收谱测试表明,在该催化剂中,界面Zn原子电荷向Bi原子转移,形成了富电子的Bi_(2)O_(2)CO_(3)表面,有利于CO_(2)的捕获和活化;而异质结构引起的压缩应力有利于优化反应中间体的吸附能,二者协同提高了Bi_(2)O_(2)CO_(3)/ZnO电催化CO_(2)还原生成甲酸的选择性和活性.展开更多
基金supported by the Taishan Scholar Program of Shandong Province,China (tsqn202211162)the National Natural Science Foundation of China (22102079)the Natural Science Foundation of Shandong Province of China (ZR2021YQ10,ZR2022QB163)。
文摘The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct activity-stability trade-off model is full of significance but challenging.Herein,a single atom Zn stabilized RuO_(2)with enriched oxygen vacancies(SA Zn-RuO_(2))is developed as a promising alternative to iridium oxide for acidic oxygen evolution reaction(OER).Compared with commercial RuO_(2),the enhanced Ru–O bond strength of SA Zn-RuO_(2)by forming Zn-O-Ru local structure motif is favorable to stabilize surface Ru,while the electrons transferred from Zn single atoms to adjacent Ru atoms protects the Ru active sites from overoxidation.Simultaneously,the optimized surrounding electronic structure of Ru sites in SA ZnRuO_(2)decreases the adsorption energies of OER intermediates to reduce the reaction barrier.As a result,the representative SA Zn-RuO_(2)exhibits a low overpotential of 210 mV to achieve 10 mA cm^(-2)and a greatly enhanced durability than commercial RuO_(2).This work provides a promising dual-engineering strategy by coupling single atom doping and vacancy for the tradeoff of high activity and catalytic stability toward acidic OER.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.RS-2023-00213920,NRF-2021R1A4A1031761).
文摘Herein,the impact of the independent control of processing additives on vertical phase separation in sequentially deposited (SD) organic photovoltaics (OPVs) and its subsequent effects on charge carrier kinetics at the electron donor-acceptor interface are investigated.The film morphology exhibits notable variations,significantly depending on the layer to which 1,8-diiodooctane (DIO) was applied.Grazing incidence wide-angle X-ray scattering analysis reveals distinctly separated donor/acceptor phases and vertical crystallinity details in SD films.Time-of-flight secondary ion mass spectrometry analysis is employed to obtain component distributions in diverse vertical phase structures of SD films depending on additive control.In addition,nanosecond transient absorption spectroscopy shows that DIO control significantly affects the dynamics of separated charges in SD films.In SD OPVs,DIO appears to act through distinct mechanisms with minimal restriction,depending on the applied layer.This study emphasizes the significance of morphological optimization in improving device performance and underscores the importance of independent additive control in the advancement of OPV technology.
基金National Research Foundation of Korea,Grant/Award Numbers:NRF‐2019M3D1A1079303,NRF‐2021R1A2C1011415,NRF‐2021R1A2C3004019。
文摘Atomically‐dispersed copper sites coordinated with nitrogen‐doped carbon(Cu–N–C)can provide novel possibilities to enable highly selective and active electrochemical CO_(2) reduction reactions.However,the construction of optimal local electronic structures for nitrogen‐coordinated Cu sites(Cu–N_(4))on carbon remains challenging.Here,we synthesized the Cu–N–C catalysts with atomically‐dispersed edge‐hosted Cu–N_(4) sites(Cu–N_(4)C_(8))located in a micropore between two graphitic sheets via a facile method to control the concentration of metal precursor.Edge‐hosted Cu–N_(4)C_(8) catalysts outperformed the previously reported M–N–C catalysts for CO_(2)‐to‐CO conversion,achieving a maximum CO Faradaic efficiency(FECO)of 96%,a CO current density of–8.97 mA cm^(–2) at–0.8 V versus reversible hydrogen electrode(RHE),and over FECO of 90%from–0.6 to–1.0 V versus RHE.Computational studies revealed that the micropore of the graphitic layer in edge‐hosted Cu–N_(4)C_(8) sites causes the d‐orbital energy level of the Cu atom to shift upward,which in return decreases the occupancy of antibonding states in the*COOH binding.This research suggests new insights into tailoring the locally coordinated structure of the electrocatalyst at the atomic scale to achieve highly selective electrocatalytic reactions.
基金National Natural Science Foundation of China,Grant/Award Number:22102079Taishan Scholar Program of Shandong Province,China,Grant/Award Number:tsqn202211162Natural Science Foundation of Shandong Province of China,Grant/Award Numbers:ZR2021YQ10,ZR2022QB163。
文摘Electrocatalytic CO_(2)-to-formate conversion is considered an economically viable process.In general,Zn-based nanomaterials are well-known to be highly efficient electrocatalysts for the conversion of CO_(2) to CO,but seldom do they exhibit excellent selectivity toward formate.In this article,we demonstrate that a heterointerface catalyst ZnO/ZnSnO3 with nanosheet morphology shows enhanced selectivity with a maximum Faradaic efficiency(FE)of 86%at−0.9 V versus reversible hydrogen electrode and larger current density for the conversion of CO_(2) to formate than pristine ZnO and ZnSnO3.In particular,the FEs of the C1 products(CO+HCOO−)exceed 98%over the potential window.The experimental measurements combined with theoretical calculations revealed that the ZnO in ZnO/ZnSnO3 heterojunction delivers the valence electron depletion and accordingly optimizes Zn d-band center,which results in moderate Zn-O hybridization of HCOO*and weakened Zn-C hybridization of competing COOH*,thus greatly boosting the HCOOH generation.Our study highlights the importance of charge redistribution in catalysts on the selectivity of electrochemical CO_(2) reduction.
基金National Research Foundation (NRF) of Korea grant funded by the Korea Government (MSIT) (NRF-2022R1A2C2093415)partially funding from the Circle Foundation (Republic of Korea) (Grant Number: 2023 TCF Innovative Science Project-03))partially Korea Basic Science Institute (National Research Facilities and Equipment Center) grant funded by the Ministry of Education (2022R1A6C101A751)。
文摘Utilizing sunlight to convert CO_(2) into chemical fuels could address the greenhouse effect and fossil fuel crisis,Heterojunction structure catalysts with oxygen vacancy are attractive in the field of photocatalytic CO_(2) conversion.Herein,a modified TiO_(2)/In_(2)O_(3)(R-P2 5/In_(2)O_(3-x)) type Ⅱ heterojunction composite with oxygen vacancies is designed for photocatalytic CO_(2) reduction,which exhibits excellent CO_(2) reduction activity,with a C_(2) selectivity of 56.66%(in terms of R_(electron)).In situ Fourier-transform infrared spectroscopy(DRIFTS) and time-resolved photoluminescence(TR-PL) spectroscopy are used to reveal the intermediate formation of the photocatalytic mechanism and photogenerated electron lifetime,respectively.The experimental characterizations reveal that the R-P25/In_(2)O_(3-x) composite shows a remarkable behavior for coupling C-C bonds.Besides,efficient charge separation contributes to the improved CO_(2) conversion performance of photocatalysts.This work introduces a type Ⅱ heterojunction composite photocatalyst,which promotes understanding the CO_(2) reduction mechanisms on heterojunction composites and is valuable for the development of photocatalysts.
基金supported by the National Research Foundation of Korea(NRF)grants funded by the Korean Government(NRF-2021R1A4A1030318,NRF-2022R1C1C1011386,NRF-2020M3H4A1A03084258)supported by the"Regional Innovation Strategy(RIS)"through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(MOE)(2021RIS-003)
文摘The layeredδ-MnO_(2)(dMO)is an excellent cathode material for rechargeable aqueous zinc-ion batteries owing to its large interlayer distance(~0.7 nm),high capacity,and low cost;however,such cathodes suffer from structural degradation during the long-term cycling process,leading to capacity fading.In this study,a Co-doped dMO composite with reduced graphene oxide(GC-dMO)is developed using a simple cost-effective hydrothermal method.The degree of disorderness increases owing to the hetero-atom doping and graphene oxide composites.It is demonstrated that layered dMO and GC-dMO undergo a structural transition from K-birnessite to the Zn-buserite phase upon the first discharge,which enhances the intercalation of Zn^(2+)ions,H_(2)O molecules in the layered structure.The GC-dMO cathode exhibits an excellent capacity of 302 mAh g^(-1)at a current density of 100 mAg^(-1)after 100 cycles as compared with the dMO cathode(159 mAhg^(-1)).The excellent electrochemical performance of the GC-dMO cathode owing to Co-doping and graphene oxide sheets enhances the interlayer gap and disorderness,and maintains structural stability,which facilitates the easy reverse intercalation and de-intercalation of Zn^(2+)ions and H_(2)O molecules.Therefore,GC-dMO is a promising cathode material for large-scale aqueous ZIBs.
基金This study was supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.2019R1F1A1062193).
文摘Pt-Ni alloy nanocrystals with Pt-enriched shells were prepared by selective etching of surface Ni using sulfuric acid and hydroquinone.The changes in the electronic and geometric structure of the alloy nanoparticles at the surface were elucidated from the electrochemical surface area,the potential of zero total charge(PZTC),and relative surface roughness,which were determined from CO-and CO_(2)-displacement experiments before and after 3000 potential cycles under oxygen reduction reaction conditions.While the highest activity and durability were achieved in hydroquinone-treated Pt–Ni,sulfuric acidtreated one showed the lower activity and durability despite its higher surface Pt concentration and alloying level.Both PZTC and QCO_(2)/QCO ratio(desorption charge of reductively adsorbed CO_(2) normalized by COad-stripping charge)depend on surface roughness.In particular,QCO_(2)/QCO ratio change better reflects the roughness on an atomic scale,and PZTC is also affected by the electronic modification of Pt atoms in surface layers.In this study,a comparative study is presented to find a relationship between surface structure and electrochemical properties,which reveals that surface roughness plays a critical role to improve the electrochemical performance of Pt-Ni alloy catalysts with Pt-rich surfaces.
基金supported by the Climate Change Response Project (NRF-2019M1A2A2065612)the Brainlink Project (NRF2022H1D3A3A01081140)+3 种基金the NRF-2021R1A4A3027878 and the No. RS-2023-00212273 funded by the Ministry of Science and ICT of Korea via National Research Foundationresearch funds from Hanhwa Solutions Chemicals (1.220029.01)UNIST (1.190013.01)supported by the Institute for Basic Science (IBS-R019-D1)。
文摘Electrochemical N_(2) reduction reaction(eNRR) over Cu-based catalysts suffers from an intrinsically low activity of Cu for activation of stable N_(2) molecules and the limited supply of N_(2) to the catalyst due to its low solubility in aqueous electrolytes.Herein,we propose phosphorus-activated Cu electrocatalysts to generate electron-deficient Cu sites on the catalyst surface to promote the adsorption of N_(2) molecules.The eNRR system is further modified using a gas diffusion electrode(GDE) coated with polytetrafluoroethylene(PTFE) to form an effective three-phase boundary of liquid water-gas N_(2)-solid catalyst to facilitate easy access of N_(2) to the catalytic sites.As a result,the new catalyst in the flow-type cell records a Faradaic efficiency of 13.15% and an NH_(3) production rate of 7.69 μg h^(-1) cm^(-2) at-0.2 V_(RHE),which represent 3.56 and 59.2 times increases from those obtained with a pristine Cu electrode in a typical electrolytic cell.This work represents a successful demonstration of dual modification strategies;catalyst modification and N_(2) supplying system engineering,and the results would provide a useful platform for further developments of electrocatalysts and reaction systems.
基金supported by Taishan Scholar Program of Shandong Province,China(ts201712045)the Doctoral Found of QUST(0100229001)2019 Research Funds(1.190002.01)of Ulsan National Institute of Science and Technology(UNIST)。
文摘For high-efficiency NH_(3)synthesis via ambient-condition electrohydrogenation of inert N_(2),it is pivotal to ingeniously design an active electrocatalyst with multiple features of abundant surfacial deficiency,good conductivity and large surface area.Here,oxygen-deficient SnO_(2)nanoparticles encapsulated by ultrathin carbon layer(d-SnO_(2)@C)are developed by hydrothermal deposition coupled with annealing process,as promising catalysts for ambient electrocatalytic N_(2)reduction.d-SnO_(2)@C exhibits high activity and excellent selectivity for electrocatalytic conversion of N_(2)to NH_(3)in acidic electrolytes,with Faradic efficiency as high as 12.7%at-0.15 V versus the reversible hydrogen electrode(RHE)and large NH_(3)yield rate of 16.68μg h^(-1)mgcat^(-1)at-0.25 V vs.RHE in 0.1 mol L^(-1)HCl.Benefiting from the structural superiority of enhanced charge transfer efficiency and optimized surface states,d-SnO_(2)@C also achieves excellent long-term stability.
基金supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT)(NRF-2022R1A2C2093415) and (NRF-2018R1A2B6006721)Institute for Basic Science of Korea (IBS-R011-D1)the Korea Medical Device Development Fund grant funded by the Korean government (the Ministry of Science and ICT, the Ministry of Trade, Industry and Energy, the Ministry of Health & Welfare, the Ministry of Food and Drug Safety) (Project Number: KMDF_PR_20200901_0004)。
文摘Herein, a stable and efficient CoS_(2)-ReS_(2) electrocatalyst is successfully constructed by using the different molar ratios of CoS_(2) on ReS_(2). The size and morphology of the catalysts are significantly changed after the CoS_(2) is grown on ReS_(2), providing regulation of the catalytic activity of ReS_(2). Particularly, the optimized CoS_(2)-ReS_(2) shows superior electrocatalytic properties with a low voltage of 1.48 V at 20 mA cm^(-2) for overall water splitting in 1.0 M KOH, which is smaller than the noble metal-based catalysts(1.77 V at 20 mA cm^(-2)). The XPS, XAS, and theoretical data confirm that the interfacial regulation of ReS_(2) by CoS_(2) can provide rich edge catalytic sites, which greatly optimizes the catalytic kinetics and drop the energy barrier for oxygen/hydrogen evolution reactions. Our results demonstrated that interfacial engineering is an efficient route for fabricating high-performance water splitting electrocatalysts.
文摘Iron sulfides have bee n con sidered as one of the most promising can didates for sodium ion battery anode materials due to their high theoretical capacity and low cost. I n this work, spin dle-like Fe7S8 with n itroge rvdoped carb on (FeiS/N-C) nano hybrids are successfully syn thesized via a solvothermal method by sulfidation iron-based metal organic framework (FeMOF). As sodium ion battery an odes, FeySs/N-C nano hybrids exhibit high reversible capacity of 450.8 mAh g-1 at 200 mA·g^-1, and 406.7 mAh·g^-1 at 500 mA·g^-1 even after 500 cycles. They also show excellent rate properties and delivering the capacity of 327.8 mAh·g^-1 at a very high current density of 3.2 A·g^-1. These outstanding electrochemical performa nces can be attributed to the unique structure of Fe7S8/ N-C nan ohybrids. The nano scale dime nsion in their size can be ben eficial for facile ion and electro n tran sports. Furthermore, the stable n itroge n doped carb on frameworks can also improve electrical conductivity and relieve the problems related to volume expansion. X-ray absorption spectroscopy and X-ray photoelectron spectroscopy analyses have been performed to study reactions occurred in spindle-like FeySs/N-C nanohybrid electrode at both bulk and surface.
文摘High energy ball-milled iron sulfides with thin carb on layer coati ng(BM-FeS/C composites)were prepared by the simple and econo mical process.Ball-milled process,followed by carb on coati ng,reduced the particle size and increased the electrical con ductivity.Whe n employed as sodium-ion battery ano des,BM?F eS/C composites showed extremely high electrochemical performa nee with reversible specific capacity of 589.8 mAh·g^-1 after 100 cycles at a current density of 100 mA·g^-1.They also exhibited superior rate capabilities of 375.9 mAh·g^-1 even at 3.2 Ag^1 and 423.6 mAh·g^-1 at 1.5 Ag_1.X-ray absorptio n near edge structure an alysis con firmed the electrochemical pathway for con version reaction of BM-FeS/C composites.
基金Taishan Scholar Program of Shandong Province,China(ts201712045)Shandong Provincial Key Research and Development Program(2019GGX102069)+2 种基金the Natural Science Foundation of Shandong Province of China(ZR2018BB008)Doctoral Found of Qingdao University of Science and Technology(0100229001 and 010029081)2019 Research Funds of Ulsan National Institute of Science and Technology,South Korea(1.190002.01).
文摘Electronic coupling with the support plays a crucial role in boosting the intrinsic catalytic activity of a single-atom catalyst.Herein,the three-dimensional(3D)hierarchical Co(OH)F nanosheet arrays modified by singleatom Ru(SA-Ru/Co(OH)F)are prepared by a facile one-step hydrothermal method under mild conditions,which exhibit excellent activity with an overpotential of 200 and 326 mV at 10 and 500 mA cm^(−2),respectively,as well as robust stability for oxygen evolution reaction(OER)in 1.0 mol L^(−1)KOH electrolyte.The study of electronic structures and surface chemical states before and after OER testing reveals that the strong electronic coupling between single-atom Ru and Co(OH)F induces the charge redistribution in SA-Ru/Co(OH)F and suppresses the excessive oxidation of Ru into higher valence state(more than+4)under high OER potential.This work provides a strategy to stabilize single-atom Ru by Co(OH)F that can enhance the activity and durability for OER under large current densities.
基金supported by Taishan Scholar Program of Shandong Province(ts201712045)the National Natural Science Foundation of China(22102079)the Natural Science Foundation of Shandong Province of China(ZR2021YQ10)。
文摘表面应力耦合异质结构是一种改善非均相催化剂催化性能的有效策略.它可以在调控催化剂电子结构的同时,促进电荷传输.一般来说,Bi基催化剂对CO_(2)电还原为甲酸的选择性高于ZnO,但是金属Bi的价格高于Zn.本文以十六烷基三甲基溴化铵为模板剂,通过一步水热法合成了一种具有多孔纳米片形貌的Bi_(2)O_(2)CO_(3)/ZnO异质结催化剂,用于高效电催化CO_(2)还原制备甲酸.在-1.0 V vs.RHE下,该催化剂展现出最大甲酸盐法拉第效率(92%),且在施加-1.2 V vs.RHE电压下甲酸盐偏电流密度为200 m A mg_(Bi)^(-1).更重要的是,对Bi的质量进行归一化发现,Bi_(2)O_(2)CO_(3)/ZnO的质量活度比纯Bi_(2)O_(2)CO_(3)的质量活度提升了3.1倍.通过X-射线光电子能谱和X-射线吸收谱测试表明,在该催化剂中,界面Zn原子电荷向Bi原子转移,形成了富电子的Bi_(2)O_(2)CO_(3)表面,有利于CO_(2)的捕获和活化;而异质结构引起的压缩应力有利于优化反应中间体的吸附能,二者协同提高了Bi_(2)O_(2)CO_(3)/ZnO电催化CO_(2)还原生成甲酸的选择性和活性.
