Designing and synthesizing high-efficiency non-precious metal-based catalysts having uniform active sites increases the reactivity and selectivity of materials and provides a platform for an in-depth understanding of ...Designing and synthesizing high-efficiency non-precious metal-based catalysts having uniform active sites increases the reactivity and selectivity of materials and provides a platform for an in-depth understanding of their catalytic reaction mechanism.In this study,we provided an approach for fabricating isolated nickel single-atom sites(Ni SAs)with high loading(4.9 wt.%)stabilized on nitrogen-doped hollow carbon spheres(NHCS)using a core–shell structured Zn/Ni bimetallic zeolitic imidazolate framework(ZIF)composite as the sacrificial template.The as-fabricated Ni SAs/NHCS catalyst shows superior activity,selectivity,and recycling durability for the catalytic transfer hydrogenation of nitrobenzene to aniline,thus achieving 100%yield of aniline with a turn-over frequency(TOF)value as high as 29.9 h^(−1) under mild conditions.This TOF value is considerably superior to the supported Ni nanoparticle catalysts.The experiments designed show that the hollow structure feature of NHCS facilitates accessible active sites and mass transfer,which thus contributes to the enhancement of the catalytic performance of Ni SAs/NHCS.Density functional theory calculations show the high chemo-selectivity and activity of the Ni SAs catalyst,arising from the unique role of the single Ni-N3 site on simultaneously activating the H donor(N_(2)H_(4))and substrate,as well as the hydrogenation of the–NOH group as the rate-determining step.展开更多
基金the National Natural Science Foundation of China(Nos.21576243 and 21701168)Natural Science Foundation of Zhejiang Province(Nos.LY18B060006,LY17B060001,and LY21B030003)+2 种基金the National Key R&D Program of China(No.2020YFA0406101)Dalian high level talent innovation project(No.2019RQ063)Open project Foundation of State Key Laboratory of Structural Chemistry,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences(No.20200021).
文摘Designing and synthesizing high-efficiency non-precious metal-based catalysts having uniform active sites increases the reactivity and selectivity of materials and provides a platform for an in-depth understanding of their catalytic reaction mechanism.In this study,we provided an approach for fabricating isolated nickel single-atom sites(Ni SAs)with high loading(4.9 wt.%)stabilized on nitrogen-doped hollow carbon spheres(NHCS)using a core–shell structured Zn/Ni bimetallic zeolitic imidazolate framework(ZIF)composite as the sacrificial template.The as-fabricated Ni SAs/NHCS catalyst shows superior activity,selectivity,and recycling durability for the catalytic transfer hydrogenation of nitrobenzene to aniline,thus achieving 100%yield of aniline with a turn-over frequency(TOF)value as high as 29.9 h^(−1) under mild conditions.This TOF value is considerably superior to the supported Ni nanoparticle catalysts.The experiments designed show that the hollow structure feature of NHCS facilitates accessible active sites and mass transfer,which thus contributes to the enhancement of the catalytic performance of Ni SAs/NHCS.Density functional theory calculations show the high chemo-selectivity and activity of the Ni SAs catalyst,arising from the unique role of the single Ni-N3 site on simultaneously activating the H donor(N_(2)H_(4))and substrate,as well as the hydrogenation of the–NOH group as the rate-determining step.
