Defect engineering,especially oxygen vacancies(O-vacancies) introduction into metal oxide materials has been proved to be an effective strategy to manipulate their surface electron exchange processes.However,quantitat...Defect engineering,especially oxygen vacancies(O-vacancies) introduction into metal oxide materials has been proved to be an effective strategy to manipulate their surface electron exchange processes.However,quantitative investigation of O-vacancies on CO2 electroreduction still remains rather ambiguous.Herein,a series of nanoporous tin oxide(SnOx) materials have been prepared by thermal treatment at various temperatures and reaction conditions.The annealing temperature dependent Ovacancies property of the SnOx was revealed and attributed to the balance tunning of the desorption of oxygen species and the continous oxidation of SnOx.The as-prepared nanoporous SnOx with 300℃treatment was found to be highest O-vacant material and showed an impressive CO2 RR activity and selectivity towards the conversion of CO2 into formic acid(up to 88.6%),and superior HCOOH incomplete current density to other samples.The ideal performance of the O-vacancies rich SnOx-300 material can be ascribed to the high delocalized electron density inducing much enhanced adsorption of CO2 with O binding and benefiting the subsequent reduction with high selectively forming of formic acid.展开更多
The electrochemical reduction of CO2 to give CO in the presence of O2 would allow the direct valorization of flue gases from fossil fuel combustion and of CO2 captured from air. However, it is a challenging task becau...The electrochemical reduction of CO2 to give CO in the presence of O2 would allow the direct valorization of flue gases from fossil fuel combustion and of CO2 captured from air. However, it is a challenging task because O2 reduction is thermodynamically favored over that of CO2. 5% O2 in CO2 near catalyst surface is sufficient to completely inhibit the CO2 reduction reaction. Here we report an O2-tolerant catalytic CO2 reduction electrode inspired by part of the natural photosynthesis unit. The electrode comprises of heterogenized cobalt phthalocyanine molecules serving as the cathode catalyst with >95% Faradaic efficiency(FE) for CO2 reduction to CO coated with a polymer of intrinsic microporosity that works as a CO2-selective layer with a CO2/O2 selectivity of $20. Integrated into a flow electrolytic cell, the hybrid electrode operating with a CO2 feed gas containing 5% O2 exhibits a FECOof 75.9% with a total current density of 27.3 mA/cm^2 at a cell voltage of 3.1 V. A FECO of 49.7% can be retained when the O2 fraction increases to 20%. Stable operation for 18 h is demonstrated. The electrochemical performance and O2 tolerance can be further enhanced by introducing cyano and nitro substituents to the phthalocyanine ligand.展开更多
Clearly understanding the structure-function relationship and rational design of efficient CO2 electrocatalysts are still the challenges.This article describes the molecular origin of high selectivity of formic acid o...Clearly understanding the structure-function relationship and rational design of efficient CO2 electrocatalysts are still the challenges.This article describes the molecular origin of high selectivity of formic acid on N-doped SnO2 nanoparticles,which obtained via thermal treatment of g-C3N4 and SnCl2·2H2O precursor.Combined with density functional theory(DFT)calculations,we discover that N-doping effectively introduces oxygen vacancies and increases the charge density of Sn sites,which plays a positive role in CO2 activation.In addition,N-doping further regulates the adsorption energy of^*OCHO,^*COOH,^*H and promotes HCOOH generation.Benefited from above modulation,the obtained N-doped SnO2 catalysts with oxygen vacancies(Ov-N-SnO2)exhibit faradaic efficiency of 93% for C1 formation,88% for HCOOH production and well-suppression of H2 evolution over a wide range of potentials.展开更多
Electrochemical conversion of CO2 to hydrocarbons can relieve both environmental and energy stresses. However, electrocatalysts for this reaction usually suffer from a poor product selectivity and a large overpotentia...Electrochemical conversion of CO2 to hydrocarbons can relieve both environmental and energy stresses. However, electrocatalysts for this reaction usually suffer from a poor product selectivity and a large overpotential. Here we report that tunable catalytic selectivity for hydrocarbon formation could be achieved on Cu nanomaterials with different morphologies. By tuning the electrochemical parameters, either Cu oxide nanowires or nanoneedles were fabricated and then electrochemically reduced to the corresponding Cu nanomaterials. The Cu nanowires preferred the formation of C2H4, while the Cu nanoneedles favored the production of more CH4, rather than C2H4. Our work provides a facile synthetic strategy for preparing Cu-based nanomaterials to achieve selective CO2 reduction.展开更多
基金supported by the National Natural Science Foundation of China,National Key Research and Development Project (No.2016YFF0204402)the Program for Changjiang Scholars and Innovative Research Team in the University+1 种基金the Fundamental Research Funds for the Central Universitiesthe longterm subsidy mechanism from the Ministry of Finance and the Ministry of Education of PRC
文摘Defect engineering,especially oxygen vacancies(O-vacancies) introduction into metal oxide materials has been proved to be an effective strategy to manipulate their surface electron exchange processes.However,quantitative investigation of O-vacancies on CO2 electroreduction still remains rather ambiguous.Herein,a series of nanoporous tin oxide(SnOx) materials have been prepared by thermal treatment at various temperatures and reaction conditions.The annealing temperature dependent Ovacancies property of the SnOx was revealed and attributed to the balance tunning of the desorption of oxygen species and the continous oxidation of SnOx.The as-prepared nanoporous SnOx with 300℃treatment was found to be highest O-vacant material and showed an impressive CO2 RR activity and selectivity towards the conversion of CO2 into formic acid(up to 88.6%),and superior HCOOH incomplete current density to other samples.The ideal performance of the O-vacancies rich SnOx-300 material can be ascribed to the high delocalized electron density inducing much enhanced adsorption of CO2 with O binding and benefiting the subsequent reduction with high selectively forming of formic acid.
基金supported by the U.S. National Science Foundation (CHE-1651717)the Croucher Fellowship for Postdoctoral Research+1 种基金supported by Global Innovation Initiative from Institute of International Educationsupport from Shenzhen Fundamental Research Funding (JCYJ20160608140827794)
文摘The electrochemical reduction of CO2 to give CO in the presence of O2 would allow the direct valorization of flue gases from fossil fuel combustion and of CO2 captured from air. However, it is a challenging task because O2 reduction is thermodynamically favored over that of CO2. 5% O2 in CO2 near catalyst surface is sufficient to completely inhibit the CO2 reduction reaction. Here we report an O2-tolerant catalytic CO2 reduction electrode inspired by part of the natural photosynthesis unit. The electrode comprises of heterogenized cobalt phthalocyanine molecules serving as the cathode catalyst with >95% Faradaic efficiency(FE) for CO2 reduction to CO coated with a polymer of intrinsic microporosity that works as a CO2-selective layer with a CO2/O2 selectivity of $20. Integrated into a flow electrolytic cell, the hybrid electrode operating with a CO2 feed gas containing 5% O2 exhibits a FECOof 75.9% with a total current density of 27.3 mA/cm^2 at a cell voltage of 3.1 V. A FECO of 49.7% can be retained when the O2 fraction increases to 20%. Stable operation for 18 h is demonstrated. The electrochemical performance and O2 tolerance can be further enhanced by introducing cyano and nitro substituents to the phthalocyanine ligand.
基金supported by the National Key R&D Program of China (2016YFB0600901)the National Natural Science Foundation of China (21525626, 21606169, 21722608)the Program of Introducing Talents of Discipline to Universities (B06006)
文摘Clearly understanding the structure-function relationship and rational design of efficient CO2 electrocatalysts are still the challenges.This article describes the molecular origin of high selectivity of formic acid on N-doped SnO2 nanoparticles,which obtained via thermal treatment of g-C3N4 and SnCl2·2H2O precursor.Combined with density functional theory(DFT)calculations,we discover that N-doping effectively introduces oxygen vacancies and increases the charge density of Sn sites,which plays a positive role in CO2 activation.In addition,N-doping further regulates the adsorption energy of^*OCHO,^*COOH,^*H and promotes HCOOH generation.Benefited from above modulation,the obtained N-doped SnO2 catalysts with oxygen vacancies(Ov-N-SnO2)exhibit faradaic efficiency of 93% for C1 formation,88% for HCOOH production and well-suppression of H2 evolution over a wide range of potentials.
文摘Electrochemical conversion of CO2 to hydrocarbons can relieve both environmental and energy stresses. However, electrocatalysts for this reaction usually suffer from a poor product selectivity and a large overpotential. Here we report that tunable catalytic selectivity for hydrocarbon formation could be achieved on Cu nanomaterials with different morphologies. By tuning the electrochemical parameters, either Cu oxide nanowires or nanoneedles were fabricated and then electrochemically reduced to the corresponding Cu nanomaterials. The Cu nanowires preferred the formation of C2H4, while the Cu nanoneedles favored the production of more CH4, rather than C2H4. Our work provides a facile synthetic strategy for preparing Cu-based nanomaterials to achieve selective CO2 reduction.
