通过 Au 掺杂调节 MOF 模板 Co@NC 催化剂的 Co-Nx 活性位点以促进醇的氧化酯化,通过 Au 掺杂调节 MOF 模板 Co@NC 催化剂的 Co-Nx 活性位点以促进醇的氧化酯化,ACS Catalysis

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通过 Au 掺杂调节 MOF 模板 Co@NC 催化剂的 Co-Nx 活性位点以促进醇的氧化酯化,通过 Au 掺杂调节 MOF 模板 Co@NC 催化剂的 Co-Nx 活性位点以促进醇的氧化酯化
ACS Catalysis ( IF 11.3 ) Pub Date : 2022-11-06 , DOI: 10.1021/acscatal.2c04837
Ruiyi Wang ₁ , Kuan Lu ₁ , Jin Zhang _{1,

2} , Xincheng Li _{1,

2} , Zhanfeng Zheng _{1,

2}

Affiliation

Co-N _x活性位点在多相催化中对 Co@NC 催化剂起着至关重要的作用。_{然而，调控Co- Nx}活性位点的含量和电子结构以提高多相催化剂催化效率的有效方法仍然不足。_{在此，通过 HAuCl 4}修饰的 ZIF-67的热解，通过 Au 掺杂策略设计了一种在外碳层中具有丰富且富电子的 Co-N _x位点的氮掺杂多孔碳包封 Au 掺杂 Co 纳米粒子催化剂金属有机骨架前体。最佳催化剂在醇选择性氧化酯化中表现出改进的催化性能。酯收率与Co-N呈线性关系_x物种含量，结合一系列对照实验，表明 Co-N_x活性位点对于实现优异的催化活性至关重要（产率：99.9％）。原位漫反射红外傅立叶变换光谱、O₂程序升温脱附表征、活性氧猝灭实验以及密度泛函理论计算结果表明，Co纳米粒子核中的Au掺杂增加了Co-N的含量和电子密度碳壳上的_x_{物种，增强分子O 2}的化学吸附和活化以产生活性O₂^•–物种。本研究展示了一种新型 Co-N _x活性位点调节策略，可在温和反应条件下有效地选择性氧化酯化醇。,Co-N _x活性位点在多相催化中对 Co@NC 催化剂起着至关重要的作用。_{然而，调控Co- Nx}活性位点的含量和电子结构以提高多相催化剂催化效率的有效方法仍然不足。_{在此，通过 HAuCl 4}修饰的 ZIF-67的热解，通过 Au 掺杂策略设计了一种在外碳层中具有丰富且富电子的 Co-N _x位点的氮掺杂多孔碳包封 Au 掺杂 Co 纳米粒子催化剂金属有机骨架前体。最佳催化剂在醇选择性氧化酯化中表现出改进的催化性能。酯收率与Co-N呈线性关系_x物种含量，结合一系列对照实验，表明 Co-N_x活性位点对于实现优异的催化活性至关重要（产率：99.9％）。原位漫反射红外傅立叶变换光谱、O₂程序升温脱附表征、活性氧猝灭实验以及密度泛函理论计算结果表明，Co纳米粒子核中的Au掺杂增加了Co-N的含量和电子密度碳壳上的_x_{物种，增强分子O 2}的化学吸附和活化以产生活性O₂^•–物种。本研究展示了一种新型 Co-N _x活性位点调节策略，可在温和反应条件下有效地选择性氧化酯化醇。

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Regulation of the Co–Nx Active Sites of MOF-Templated Co@NC Catalysts via Au Doping for Boosting Oxidative Esterification of Alcohols

The Co–N_x active sites play a critical role over the Co@NC catalyst in the heterogeneous catalysis. However, the effective methods for the regulation of the content and electronic structure of Co–N_x active sites to enhance the catalytic efficiency of heterogeneous catalysts are still insufficient. Herein, a nitrogen-doped porous carbon-encapsulated Au-doped Co nanoparticle catalysts with abundant and electron-rich Co–N_x sites in the outer carbon layer was designed by a Au doping strategy through pyrolysis of the HAuCl₄-modified ZIF-67 metal organic framework precursor. The optimal catalyst exhibits improved catalytic performance in alcohol selective oxidative esterification. The linear relationship between the ester yield and Co–N_x species content, combined with a series of control experiments, indicated that the Co–N_x active sites are crucial for achieving the excellent catalytic activity (yield: 99.9%). In situ diffuse reflectance infrared Fourier transform spectroscopy, O₂-temperature-programed desorption characterizations, active oxygen species quenching experiments together with density functional theory calculations results indicate that Au doping in the Co nanoparticle core increases the content and the electron density of Co–N_x species on the outer carbon shell, which enhanced the chemical adsorption and activation of molecular O₂ for producing reactive O₂^•– species. This study demonstrated a novel Co–N_x active site regulation strategy for the efficient selective oxidative esterification of alcohols under mild reaction conditions.

更新日期：2022-11-06

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