Exploring nonprecious electrocatalysts for water splitting with high efficiency and durability is critically important.Herein,bimetallic phosphides are encapsulated into graphitized carbon to construct a C@NiCoP compo...Exploring nonprecious electrocatalysts for water splitting with high efficiency and durability is critically important.Herein,bimetallic phosphides are encapsulated into graphitized carbon to construct a C@NiCoP composite nanoarray using bimetallic metal-organic framework(MOF) as a self-sacrificial template.The resulting C@NiCoP exhibits superior performance for pH-universal electrocatalytic hydrogen evolution reaction(HER),particularly representing a low overpotential of 46.3 mV at 10 mA cm^(-2) and Tafel slope of 44.1 mV dec^(-1) in alkaline media.The structural characterizations combined with theoretical calculation demonstrate that tailored electronic structure from bimetal atoms and the synergistic effect with graphitized carbon layer could jointly optimize the adsorption ability of hydrogen on active sites in HER process,and enhance the electrical conductivity as well.In addition,the carbon layer served as a protecting shell also prevents highly dispersed NiCoP components from agglomeration and/or loss in harsh media,finally improving the durability.This work thus provides a new insight into optimizing activity and stability of pH-universal electrocatalysts by the nanostructural design and electronic structure modulation.展开更多
Enhancing electrocatalytic water splitting performance by modulating the intrinsic electronic structure is of great importance. Here, porous bimetallic oxide and chalcogenide nanosheets grown on carbon paper denoted a...Enhancing electrocatalytic water splitting performance by modulating the intrinsic electronic structure is of great importance. Here, porous bimetallic oxide and chalcogenide nanosheets grown on carbon paper denoted as NiCo2X4/CP (X = O, S, and Se) are prepared to demonstrate how the anion components affect the electronic structures and thereby disclose the correlation between their intermediates interaction and catalytic activities. The experimental characterization and theoretical calculation demonstrate that Se and S substitution can promote the ratio of Co^(3+)/Co^(2+) and thereby modulate the electronic structure accompanied with the upshift of d band centers, which not only enhance the inner conductivity but also regulate the interaction between the catalyst surface and intermediates, especially for the adsorption of absorbed H and hydroperoxy intermediates towards respective hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). As a result, a full alkaline electrolyzer using NiCo2Se4/CP and NiCo2S4/CP as cathode and anode delivers a low voltage of 1.51 V at 10 mA·cm^(−2), which is comparable even superior to most transition metal-based electrolyzers.展开更多
Photocatalytic CO_(2)reduction to convert solar energy to clean energy remains a critical challenge in exploring efficient catalysts.Herein,a hierarchical structured BiVO4@Au@UiO-66-NH_(2)with high photocatalytic acti...Photocatalytic CO_(2)reduction to convert solar energy to clean energy remains a critical challenge in exploring efficient catalysts.Herein,a hierarchical structured BiVO4@Au@UiO-66-NH_(2)with high photocatalytic activity was fabricated.The theoretical calculations revealed that the metal–organic framework(MOF)with relative higher conduction band(CB)and UiO-66-NH_(2)with relative lower valence band(VB)could absorb full light spectrum,combining Au nanoparticle with suitable Fermi level into a particulate tandem heterojunction.This configuration can not only lower the activation barrier of CO_(2)reduction using the rich active site of MOF,but also improve the selectivity toward CO by optimizing the reaction pathway.Notably,the experimental evaluation proved that BiVO4@Au@UiO-66-NH2 displays a producing rate of 232.7μmol h^(-1)g^(-1)for CO and a selectivity of 97.2%.The investigation reveals that elaborately integrating multiple functional components into such a hier-archical structure enables optimizing crucial processes in photocatalytic CO_(2)conversion and enhancing selectivity via synergistic catalysis.展开更多
基金supported by the National Natural Science Foundation of China (nos. 21771012, 22038001, 51621003)。
文摘Exploring nonprecious electrocatalysts for water splitting with high efficiency and durability is critically important.Herein,bimetallic phosphides are encapsulated into graphitized carbon to construct a C@NiCoP composite nanoarray using bimetallic metal-organic framework(MOF) as a self-sacrificial template.The resulting C@NiCoP exhibits superior performance for pH-universal electrocatalytic hydrogen evolution reaction(HER),particularly representing a low overpotential of 46.3 mV at 10 mA cm^(-2) and Tafel slope of 44.1 mV dec^(-1) in alkaline media.The structural characterizations combined with theoretical calculation demonstrate that tailored electronic structure from bimetal atoms and the synergistic effect with graphitized carbon layer could jointly optimize the adsorption ability of hydrogen on active sites in HER process,and enhance the electrical conductivity as well.In addition,the carbon layer served as a protecting shell also prevents highly dispersed NiCoP components from agglomeration and/or loss in harsh media,finally improving the durability.This work thus provides a new insight into optimizing activity and stability of pH-universal electrocatalysts by the nanostructural design and electronic structure modulation.
基金This work was supported by the National Natural Science Foundation of China(Nos.21771012,21601008)the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(No.51621003).
文摘Enhancing electrocatalytic water splitting performance by modulating the intrinsic electronic structure is of great importance. Here, porous bimetallic oxide and chalcogenide nanosheets grown on carbon paper denoted as NiCo2X4/CP (X = O, S, and Se) are prepared to demonstrate how the anion components affect the electronic structures and thereby disclose the correlation between their intermediates interaction and catalytic activities. The experimental characterization and theoretical calculation demonstrate that Se and S substitution can promote the ratio of Co^(3+)/Co^(2+) and thereby modulate the electronic structure accompanied with the upshift of d band centers, which not only enhance the inner conductivity but also regulate the interaction between the catalyst surface and intermediates, especially for the adsorption of absorbed H and hydroperoxy intermediates towards respective hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). As a result, a full alkaline electrolyzer using NiCo2Se4/CP and NiCo2S4/CP as cathode and anode delivers a low voltage of 1.51 V at 10 mA·cm^(−2), which is comparable even superior to most transition metal-based electrolyzers.
基金supported by the Grande Solution Project“HiGradeGas”(48279)Innovation Fund Denmark,exploring NFs-based adsorbents for biogas upgrading and storage+1 种基金the Danish Research Council to provide funding to support fundamental research on electrospinning(8022-00237B)for investigating NFs structures for enzyme immobilization(6111-00232B)。
基金the National Natural Science Foundation of China(21771012,21606006)the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(No.51621003)the Science&Technology Project of Beijing Municipal Education Committee(KZ201810005004)。
文摘Photocatalytic CO_(2)reduction to convert solar energy to clean energy remains a critical challenge in exploring efficient catalysts.Herein,a hierarchical structured BiVO4@Au@UiO-66-NH_(2)with high photocatalytic activity was fabricated.The theoretical calculations revealed that the metal–organic framework(MOF)with relative higher conduction band(CB)and UiO-66-NH_(2)with relative lower valence band(VB)could absorb full light spectrum,combining Au nanoparticle with suitable Fermi level into a particulate tandem heterojunction.This configuration can not only lower the activation barrier of CO_(2)reduction using the rich active site of MOF,but also improve the selectivity toward CO by optimizing the reaction pathway.Notably,the experimental evaluation proved that BiVO4@Au@UiO-66-NH2 displays a producing rate of 232.7μmol h^(-1)g^(-1)for CO and a selectivity of 97.2%.The investigation reveals that elaborately integrating multiple functional components into such a hier-archical structure enables optimizing crucial processes in photocatalytic CO_(2)conversion and enhancing selectivity via synergistic catalysis.
