Photo-assisted Mg/seawater batteries(PAMSBs)are attractive power source for marine equipment due to the advan tage of simultaneous generation of electricity an d hydrogen from seawater.Nonetheless,the serious photocor...Photo-assisted Mg/seawater batteries(PAMSBs)are attractive power source for marine equipment due to the advan tage of simultaneous generation of electricity an d hydrogen from seawater.Nonetheless,the serious photocorrosion of photocathodes results in dissatisfactory battery performan ce,which substantially hinder their practical applications.Herein,we design a CuO/Cu2O heterostructure as the photocathode of PAMSBs via a facile in-situ electrochemical strategy,successfully enhance the photo-stability of bare Cu2O.During half-cell photoelectrochemical water splitting,the newly-developed CuO/Cu2O photocathode reveals a photo-current density about 2.2 mA cm-2at 0 V(vs.RHE)and enables nearly 100% retention of the initial photocurrent density after 2h long-term operation,more than 10 times stable than the bare Cu2O photocathode.A PAMSB with a CuO/Cu2O photocathode achieves a maximum power density up to 22.67 mW cm-2and a hydrogen yield rate up to 1.18 mL cm-2min-1,much higher than those obtained with a bare Cu2O photocathode.This study offers a simple and convenient electrochemical strategy for in-situ fabrication of CuO/Cu2O heterojunction photocathodes,and also demonstrate the feasibility of PAMSBs as a power source and a hydrogen generator,which lays foundation for its future marine application.展开更多
CO preferential oxidation (CO-PROX) in rich H2 is considered a feasible strategy to solve CO poisoning for fuel cells,but obtaining good activity at low temperatures is still a challenge.Herein,three-dimensional or...CO preferential oxidation (CO-PROX) in rich H2 is considered a feasible strategy to solve CO poisoning for fuel cells,but obtaining good activity at low temperatures is still a challenge.Herein,three-dimensional ordered macroporous (3DOM) CuO/CeO2 catalysts were fabricated by a templating approach,with the metal-support interaction (MSI) adjusted through active metal loading.The 10CuO/CeO2 catalyst achieves complete CO conversion at 110℃ and demonstrates excellent stability.Characterization studies have shown that the 10CuO/CeO2 catalyst has abundant active sites and oxygen vacancies;this phenomenon could potentially be attributed to the synergistic effects arising from the MSI between CuO and CeO2.Moreover,in situ diffuse reflectance infrared Fourier transform spectra (in situ DRIFTS) were used to identify the intermediates and confirm that appropriate MSI enhances CO adsorption and activation.The findings of this study make significant contributions to the advancement of 3DOM CuO/CeO2 catalysts for CO-PROX and establish a promising strategy for optimizing the MSI in supported catalyst systems.展开更多
Carbon-carbon(C-C)coupling,the rate-determining step in electrocatalytic CO2reduction reaction(CO2RR)to C2+ products,has low efficiency and poor stability.It originates from an ineffective water dissociation ...Carbon-carbon(C-C)coupling,the rate-determining step in electrocatalytic CO2reduction reaction(CO2RR)to C2+ products,has low efficiency and poor stability.It originates from an ineffective water dissociation capability and a high energy barrier for the C-C coupling pathway on existing catalysts.Herein,an efficient and facile Br-CuO electrocatalyst was synthesized to promote water dissociation and achieve an impressive Faradic Efficiency(FE)of around 60% C2H4 at a current density of up to-350 mA/cm2 with stability of 16 h.Combinative theoretical and experimental protocols strongly evidence that the architecture of Cu0-Cu+ sites is crucial for the enhancement in CO2 RR activity.Cu0 activates CO2and Cu+ strengthens *CO adsorption to further boost C-C coupling.Furthermore,Br doping can facilitate the dissociation of water to generate *H,which promotes the protonation of *CO to *CHO,thereby enabling the low energy barrier asymmetric *CHO-*CO coupling.The in situ ATR-FTIR and Density functional theory(DFT) was analyzed to explain the reaction mechanism and pathway.This study elucidates the critical function of water dissociation and provides a promising avenue to efficient CO2-to-C2H4 electrocatalysis.展开更多
ZnAl2O4 and ZnAl2O4-based ceramics have attracted much attention from researchers due to their good microwave dielectric,thermal and mechanical properties.In this work,the influence of 5%(in mass)CuO-TiO_(...ZnAl2O4 and ZnAl2O4-based ceramics have attracted much attention from researchers due to their good microwave dielectric,thermal and mechanical properties.In this work,the influence of 5%(in mass)CuO-TiO2-Nb2O5(CTN)ternary composite oxide additives with different composition ratios on sintering behavior and properties of ZnAl2O4 microwave dielectric ceramics was investigated.When the molar fraction ranges of Cu,Ti and Nb elements in 5%CTN additives are 0.625-0.875,0-0.250 and 0.125-0.625,respectively,sintering temperature of ZnAl2O4 ceramics can be reduced from above 1400℃to below 1000℃.The sintering additives CN(Cu:Nb=1:1,molar ratio)and CTN(Cu:Ti:Nb=4:1:3,molar ratio)can reduce sintering temperature of ZnAl2O4 ceramics to 975 and 1000℃,respectively,while maintaining good dielectric properties(dielectric constantεr=11.36,quality factor Q׃=8245 GHz andεr=9.52,Q׃=22249 GHz)and flexural strengths(200 and 161 MPa),which are expected to be applied in preparation of low temperature co-fired ceramic(LTCC)materials with copper electrodes.Low-temperature sintering of the ZnAl2O4+CTN system is characterized as activated sintering.Nanometer-level amorphous interfacial films containing Cu,Ti,and Nb elements are observed at the grain boundaries,which may provide fast diffusion pathways for mass transportation during the sintering process.Valence changes of Ti and Cu ions,along with changes of oxygen vacancies,are confirmed,which provides a potential mechanism for reduced sintering temperature of ZnAl2O4 ceramics.In addition,a series of reactions occurring at the grain boundaries can activate these boundaries and further promote the sintering densification process.These results suggest a promising way to design a novel LTCC material with excellent properties based on the low temperature sintering of ceramics with the sintering aid of CuO-TiO2-Nb2O5 composite oxide.展开更多
Electrocatalytic CO2reduction reaction(CO2RR)to ethylene(C2H4)represents a promising approach to reducing CO2emissions and producing high-value chemicals.The ethylene productivity is always limited by t...Electrocatalytic CO2reduction reaction(CO2RR)to ethylene(C2H4)represents a promising approach to reducing CO2emissions and producing high-value chemicals.The ethylene productivity is always limited by the slow reaction kinetics and the high-performance catalysts are significantly desired.Many efforts have been made to develop a catalyst to activate CO2molecules.However,as another reactant,H2O activation does not receive the attention it deserves.In particular,slow H2O dissociation kinetics limit the rate of proton supply,severely impairing the production of C2H4.Here,we designed a MgO-modified CuO catalyst(MgO/CuO),which can promote H2O dissociation and enhance CO2adsorption at the same time to realize the efficient ethylene production.The optimal catalyst exhibits a Faraday efficiency for C2H4reached 54.4%at−1.4 V vs.RHE in an H-cell,which is 1.4 times that of pure CuO(37.9%),and it was further enhanced to a 56.7%in a flow cell,with a high current density of up to 535.9 mA cm−2 at−1.0 V vs.RHE.Experimental and theoretical calculations show that MgO/CuO plays a bifunctional role in the CO2RR,which facilitates the adsorption and activation of CO2by CuO and simultaneously accelerates H2O dissociation by MgO doping.The in situ XRD experiments demonstrate that the introduction of MgO protects CuO active phase to avoid overreduction and preserves the active centers for CO2RR.In combination with in situ FTIR and DFT calculations,the protonation process from*CO to*COH and asymmetric C–C coupling step are promoted by the enhanced water activation and proton coupling on MgO/CuO.This work provides new insights into the CO2and H2O coactivation mechanism in CO2RR and a potential universal strategy to design ethylene production electrocatalysts.展开更多
基金financially supported by National Natural Science Foundation of China(Nos.22179067 and 22279069)Major Fundamental Research Program of Natural Science Foundation of Shandong Province(No.ZR2022ZD10)。
摘要Photo-assisted Mg/seawater batteries(PAMSBs)are attractive power source for marine equipment due to the advan tage of simultaneous generation of electricity an d hydrogen from seawater.Nonetheless,the serious photocorrosion of photocathodes results in dissatisfactory battery performan ce,which substantially hinder their practical applications.Herein,we design a CuO/Cu2O heterostructure as the photocathode of PAMSBs via a facile in-situ electrochemical strategy,successfully enhance the photo-stability of bare Cu2O.During half-cell photoelectrochemical water splitting,the newly-developed CuO/Cu2O photocathode reveals a photo-current density about 2.2 mA cm-2at 0 V(vs.RHE)and enables nearly 100% retention of the initial photocurrent density after 2h long-term operation,more than 10 times stable than the bare Cu2O photocathode.A PAMSB with a CuO/Cu2O photocathode achieves a maximum power density up to 22.67 mW cm-2and a hydrogen yield rate up to 1.18 mL cm-2min-1,much higher than those obtained with a bare Cu2O photocathode.This study offers a simple and convenient electrochemical strategy for in-situ fabrication of CuO/Cu2O heterojunction photocathodes,and also demonstrate the feasibility of PAMSBs as a power source and a hydrogen generator,which lays foundation for its future marine application.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.21563014 and 22408136)Jiangxi Provincial Natural Science Foundation(Grant Nos.20232BAB203016and 20252BAC200238)+1 种基金the Early Career Young Scientists and Technologists Project of Jiangxi Province(Grant No.20244BCE52045)the National Research Foundation,Singapore and A*STAR under its LowCarbon Energy Research Funding Initiative Project(Grant Nos.U2102d2011,WBS:A-8000278-00-00)。
摘要CO preferential oxidation (CO-PROX) in rich H2 is considered a feasible strategy to solve CO poisoning for fuel cells,but obtaining good activity at low temperatures is still a challenge.Herein,three-dimensional ordered macroporous (3DOM) CuO/CeO2 catalysts were fabricated by a templating approach,with the metal-support interaction (MSI) adjusted through active metal loading.The 10CuO/CeO2 catalyst achieves complete CO conversion at 110℃ and demonstrates excellent stability.Characterization studies have shown that the 10CuO/CeO2 catalyst has abundant active sites and oxygen vacancies;this phenomenon could potentially be attributed to the synergistic effects arising from the MSI between CuO and CeO2.Moreover,in situ diffuse reflectance infrared Fourier transform spectra (in situ DRIFTS) were used to identify the intermediates and confirm that appropriate MSI enhances CO adsorption and activation.The findings of this study make significant contributions to the advancement of 3DOM CuO/CeO2 catalysts for CO-PROX and establish a promising strategy for optimizing the MSI in supported catalyst systems.
基金supported by the National Natural Science Foundation of China(Nos.22276064 and 2207605)the Natural Science Foundation of Fujian Province(No.2024J01095)+1 种基金the Fundamental Research Funds for Young and Middle-aged Teachers in Science and Technology Research of Huaqiao University(No.ZQN-917)the Scientific Research Funds of Huaqiao University(No.605-50Y17071).
摘要Carbon-carbon(C-C)coupling,the rate-determining step in electrocatalytic CO2reduction reaction(CO2RR)to C2+ products,has low efficiency and poor stability.It originates from an ineffective water dissociation capability and a high energy barrier for the C-C coupling pathway on existing catalysts.Herein,an efficient and facile Br-CuO electrocatalyst was synthesized to promote water dissociation and achieve an impressive Faradic Efficiency(FE)of around 60% C2H4 at a current density of up to-350 mA/cm2 with stability of 16 h.Combinative theoretical and experimental protocols strongly evidence that the architecture of Cu0-Cu+ sites is crucial for the enhancement in CO2 RR activity.Cu0 activates CO2and Cu+ strengthens *CO adsorption to further boost C-C coupling.Furthermore,Br doping can facilitate the dissociation of water to generate *H,which promotes the protonation of *CO to *CHO,thereby enabling the low energy barrier asymmetric *CHO-*CO coupling.The in situ ATR-FTIR and Density functional theory(DFT) was analyzed to explain the reaction mechanism and pathway.This study elucidates the critical function of water dissociation and provides a promising avenue to efficient CO2-to-C2H4 electrocatalysis.
基金National Natural Science Foundation of China (U24A2052)Shanghai Eastern Talent Plan。
摘要ZnAl2O4 and ZnAl2O4-based ceramics have attracted much attention from researchers due to their good microwave dielectric,thermal and mechanical properties.In this work,the influence of 5%(in mass)CuO-TiO2-Nb2O5(CTN)ternary composite oxide additives with different composition ratios on sintering behavior and properties of ZnAl2O4 microwave dielectric ceramics was investigated.When the molar fraction ranges of Cu,Ti and Nb elements in 5%CTN additives are 0.625-0.875,0-0.250 and 0.125-0.625,respectively,sintering temperature of ZnAl2O4 ceramics can be reduced from above 1400℃to below 1000℃.The sintering additives CN(Cu:Nb=1:1,molar ratio)and CTN(Cu:Ti:Nb=4:1:3,molar ratio)can reduce sintering temperature of ZnAl2O4 ceramics to 975 and 1000℃,respectively,while maintaining good dielectric properties(dielectric constantεr=11.36,quality factor Q׃=8245 GHz andεr=9.52,Q׃=22249 GHz)and flexural strengths(200 and 161 MPa),which are expected to be applied in preparation of low temperature co-fired ceramic(LTCC)materials with copper electrodes.Low-temperature sintering of the ZnAl2O4+CTN system is characterized as activated sintering.Nanometer-level amorphous interfacial films containing Cu,Ti,and Nb elements are observed at the grain boundaries,which may provide fast diffusion pathways for mass transportation during the sintering process.Valence changes of Ti and Cu ions,along with changes of oxygen vacancies,are confirmed,which provides a potential mechanism for reduced sintering temperature of ZnAl2O4 ceramics.In addition,a series of reactions occurring at the grain boundaries can activate these boundaries and further promote the sintering densification process.These results suggest a promising way to design a novel LTCC material with excellent properties based on the low temperature sintering of ceramics with the sintering aid of CuO-TiO2-Nb2O5 composite oxide.
基金supported by the National Natural Science Foundation of China(Grant No.U21B2099,U22A20425,and 22208377)Natural Science Foundation of Shandong Province(ZR2021QE062)Fundamental Research Funds for the Central Universities,Ocean University of China(grant number 202364004)。
摘要Electrocatalytic CO2reduction reaction(CO2RR)to ethylene(C2H4)represents a promising approach to reducing CO2emissions and producing high-value chemicals.The ethylene productivity is always limited by the slow reaction kinetics and the high-performance catalysts are significantly desired.Many efforts have been made to develop a catalyst to activate CO2molecules.However,as another reactant,H2O activation does not receive the attention it deserves.In particular,slow H2O dissociation kinetics limit the rate of proton supply,severely impairing the production of C2H4.Here,we designed a MgO-modified CuO catalyst(MgO/CuO),which can promote H2O dissociation and enhance CO2adsorption at the same time to realize the efficient ethylene production.The optimal catalyst exhibits a Faraday efficiency for C2H4reached 54.4%at−1.4 V vs.RHE in an H-cell,which is 1.4 times that of pure CuO(37.9%),and it was further enhanced to a 56.7%in a flow cell,with a high current density of up to 535.9 mA cm−2 at−1.0 V vs.RHE.Experimental and theoretical calculations show that MgO/CuO plays a bifunctional role in the CO2RR,which facilitates the adsorption and activation of CO2by CuO and simultaneously accelerates H2O dissociation by MgO doping.The in situ XRD experiments demonstrate that the introduction of MgO protects CuO active phase to avoid overreduction and preserves the active centers for CO2RR.In combination with in situ FTIR and DFT calculations,the protonation process from*CO to*COH and asymmetric C–C coupling step are promoted by the enhanced water activation and proton coupling on MgO/CuO.This work provides new insights into the CO2and H2O coactivation mechanism in CO2RR and a potential universal strategy to design ethylene production electrocatalysts.