山西大学杨恒权团队报道了小配体Pickering液滴界面控制金属催化剂的反应选择性。相关研究成果发表在2025年2月6日出版的《美国化学会杂志》。

特别是在不牺牲催化活性的情况下，开发有效的方法来提高催化选择性对化学合成具有至关重要的意义。

该文中，研究人员报告了一种涉及小配体的Pickering液滴界面，作为一种有效调节金属催化剂反应选择性的全新策略。研究发现，极性芳烃等小配体可以设计在Pickering液滴界面组装的Pt催化剂的表面结构。由于与水的强氢键相互作用，极性芳烃优先与覆盖Pt表面的水吸附层吸附，在Pickering乳液液滴上形成水介导的金属-有机界面。这种界面系统显示出对乙烯基苯胺选择性从8.7%显著提高到94.2%，对硝基苯氢化的转化率没有降低。

研究发现选择性与界面氢键的键长呈负线性相关。理论计算表明，小芳烃配体可以在界面上紧密排列，从而调节反应物/产物分子的吸附模式，防止C═C基团不会接近Pt表面，而不会抑制它们对反应物分子的可及性。这种显著的界面空间效应有助于有效控制氢化选择性。

该工作提供了一种创新的策略来调节金属催化剂的表面结构，为调节催化选择性开辟了新的途径。

附：英文原文

Title: Small Ligand-Involved Pickering Droplet Interface Controls Reaction Selectivity of Metal Catalysts

Author: Jie Yang, Yue Sun, Hu Shi, Houbing Zou, Yabin Zhang, Xinxin Tian, Hengquan Yang

Issue&Volume: February 6, 2025

Abstract: Developing efficient methods to improve catalytic selectivity, particularly without sacrificing catalytic activity, is of paramount significance for chemical synthesis. In this work, we report a small ligand-involved Pickering droplet interface as a brand-new strategy to effectively regulate reaction selectivity of metal catalysts. It was found that small ligands such as polar arenes could engineer the surface structure of Pt catalysts that were assembled at Pickering droplet interfaces. Due to the strong hydrogen-bonding interactions with water, the polar arenes preferentially adsorbed with the water adlayer that covered Pt surfaces, forming water-mediated metal–organic interfaces on the Pickering emulsion droplets. Such an interface system displayed a significantly enhanced p-vinylaniline selectivity from 8.7 to 94.2% with an unreduced conversion in p-nitrostyrene hydrogenation. The selectivity was found to follow a negatively linear correlation with the bond length of the interfacial hydrogen bonds. Theoretical calculations revealed that the small arene ligands could closely array at the interface, which modulated the adsorption patterns of reactant/product molecules to prevent the C═C group from approaching Pt surfaces without suppressing their accessibility toward reactant molecules. Such a remarkable interfacial steric effect contributed to the efficient control of the hydrogenation selectivity. Our work provides an innovative strategy to modulate the surface structure of metal catalysts, opening a new venue to tune catalytic selectivity.

DOI: 10.1021/jacs.4c16128

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c16128