Regulating the selectivity toward a target hydrocarbon product is still the focus of CO_(2)electroreduction.Here,we discover that the original surface Cu species in Cu gas-diffusion electrodes plays a more important r...Regulating the selectivity toward a target hydrocarbon product is still the focus of CO_(2)electroreduction.Here,we discover that the original surface Cu species in Cu gas-diffusion electrodes plays a more important role than the surface roughness,local pH,and facet in governing the selectivity toward C_(1)or C_(2)hydrocarbons.The selectivity toward C_(2)H_(4) progressively increases,while CH_(4) decreases steadily upon lowering the Cu oxidation species fraction.At a relatively low electrodeposition voltage of 1.5 V,the Cu gas-diffusion electrode with the highest Cu^(δ+)/Cu^(0)ratio favors the pathways of∗CO hydrogenation to form CH_(4) with maximum Faradaic efficiency of 65.4%and partial current density of 228 mA cm^(−2)at−0.83 V vs RHE.At 2.0 V,the Cu gas-diffusion electrode with the lowest Cu^(δ+)/Cu^(0)ratio prefers C-C coupling to form C_(2)+products with Faradaic efficiency topping 80.1%at−0.75 V vs RHE,where the Faradaic efficiency of C_(2)H_(4) accounts for 46.4%and the partial current density of C_(2)H_(4) achieves 279 mA cm^(−2).This work demonstrates that the selectivity from CH_(4) to C_(2)H_(4) is switchable by tuning surface Cu species composition of Cu gas-diffusion electrodes.展开更多
Distinct from molecular machines with frustrated dynamics,infinite framework assemblies are anticipated to behave with amplified and even synergistic performances in versatile application fields by performing their fu...Distinct from molecular machines with frustrated dynamics,infinite framework assemblies are anticipated to behave with amplified and even synergistic performances in versatile application fields by performing their functionalities in a coherent fashion.This work reports an interconverted crystalline Pd/Zr-SDC and amorphous Pd/Zr-SDC-Br metal–organic framework(MOF)system through dynamic bromination/debromination processes.In the upgrading of biomass-derived vanillin,Pd/Zr-SDC produces vanillyl alcohol intermediate via the hydrogenation route while Pd/Zr-SDC-Br switches to 2-methoxy-4-methylphenol via an alternative hydrodeoxygenation route.More significantly,quasi-crystalline Pd/Zr-SDC-Br50%intermediate through controlled debromination is further optimized for vanillin catalysis with an excellent turnover frequency of 717 h^(−1)and a high 2-methoxy-4-methylphenol selectivity up to 99.2%under very mild conditions.Both experiments and density functional theory calculation results jointly reveal that the remarkably boosted catalytic performances are attributed to the appropriate coverage of PdBr2 onto Pd nanoparticles during the dynamic debromination transitions.This work inspires guidance in designing and developing excellent MOF catalysts via dynamical structure intertransitions.展开更多
基金partially financially supported by NSF CBET-2033343.J.Z.thanks the support from National Natural Science Foundation of China(52172293,51772072,and 51672065)the Fundamental Research Funds for the Central Universities(JZ2021HGQB0282 and PA2021GDSK0088)+3 种基金financial support from the Key R&D Projects of Anhui Province(202104b11020016)the 111 Project(B18018)the National Synchrotron Light Source II,a U.S.Department of Energy(DOE)Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No.DE-SC0012704the use of facilities within the Eyring Materials Center at Arizona State University supported in part by NNCI-ECCS-1542160.
文摘Regulating the selectivity toward a target hydrocarbon product is still the focus of CO_(2)electroreduction.Here,we discover that the original surface Cu species in Cu gas-diffusion electrodes plays a more important role than the surface roughness,local pH,and facet in governing the selectivity toward C_(1)or C_(2)hydrocarbons.The selectivity toward C_(2)H_(4) progressively increases,while CH_(4) decreases steadily upon lowering the Cu oxidation species fraction.At a relatively low electrodeposition voltage of 1.5 V,the Cu gas-diffusion electrode with the highest Cu^(δ+)/Cu^(0)ratio favors the pathways of∗CO hydrogenation to form CH_(4) with maximum Faradaic efficiency of 65.4%and partial current density of 228 mA cm^(−2)at−0.83 V vs RHE.At 2.0 V,the Cu gas-diffusion electrode with the lowest Cu^(δ+)/Cu^(0)ratio prefers C-C coupling to form C_(2)+products with Faradaic efficiency topping 80.1%at−0.75 V vs RHE,where the Faradaic efficiency of C_(2)H_(4) accounts for 46.4%and the partial current density of C_(2)H_(4) achieves 279 mA cm^(−2).This work demonstrates that the selectivity from CH_(4) to C_(2)H_(4) is switchable by tuning surface Cu species composition of Cu gas-diffusion electrodes.
基金supported by the National Natural Science Foundation of China(grant nos.21905195 and 22103055)Natural Science Foundation of Tianjin City(grant no.20JCYBJC00800)+2 种基金Science and Technology Plans of Tianjin(grant no.21ZYJDJC00050)PEIYANG Young Scholars Program of Tianjin University(grant no.2020XRX-0023)Wenzhou Key Laboratory of Biomaterials and Engineering(grant no.WIUCASSWCL21005).
文摘Distinct from molecular machines with frustrated dynamics,infinite framework assemblies are anticipated to behave with amplified and even synergistic performances in versatile application fields by performing their functionalities in a coherent fashion.This work reports an interconverted crystalline Pd/Zr-SDC and amorphous Pd/Zr-SDC-Br metal–organic framework(MOF)system through dynamic bromination/debromination processes.In the upgrading of biomass-derived vanillin,Pd/Zr-SDC produces vanillyl alcohol intermediate via the hydrogenation route while Pd/Zr-SDC-Br switches to 2-methoxy-4-methylphenol via an alternative hydrodeoxygenation route.More significantly,quasi-crystalline Pd/Zr-SDC-Br50%intermediate through controlled debromination is further optimized for vanillin catalysis with an excellent turnover frequency of 717 h^(−1)and a high 2-methoxy-4-methylphenol selectivity up to 99.2%under very mild conditions.Both experiments and density functional theory calculation results jointly reveal that the remarkably boosted catalytic performances are attributed to the appropriate coverage of PdBr2 onto Pd nanoparticles during the dynamic debromination transitions.This work inspires guidance in designing and developing excellent MOF catalysts via dynamical structure intertransitions.
