大连理工大学邱介山团队报道了醇氧化中催化剂与反应物相互作用增强的水诱导效应。 相关研究成果发表在2021年4月8日出版的《美国化学会杂志》。

固体纳米粒子稳定的Pickering乳液为催化反应提供了多样化的溶剂微环境，能够促进反应底物/产物的相转移，但溶剂的内在作用尚不清楚。

该文以苯甲醇（BA）为模型反应物，研究了水促进Pd/MgAl-LDO催化剂上醇氧化活性的性质。根据溶剂中的水，研究人员在系统中的观察到关于水比例的不同反应性。动力学同位素效应证实了水对BA氧化的参与和正效应。通过水蒸气脉冲吸附与程序升温脱附相结合的方法，识别和鉴定了水的促进效应。

研究人员利用准原位拉曼光谱研究了BA和苯甲醛在Pd/MgAl-LDO界面上的吸附行为。此外，基于Langmuir-Hinshelwood机理，合理地提出了水促进醇氧化的机理。研究人员进一步证明了水促进效应在不同载体和底物上的普遍适用性，与纯甲苯体系相比，它在Pickering乳液中具有良好的催化活性和选择性。

附：英文原文

Title: Recognition of Water-Induced Effects toward Enhanced Interaction between Catalyst and Reactant in Alcohol Oxidation

Author: Qianbing Wei, Chang Yu, Xuedan Song, Yiping Zhong, Lin Ni, Yongwen Ren, Wei Guo, Jinhe Yu, Jieshan Qiu

Issue&Volume: April 8, 2021

Abstract: Pickering emulsion stabilized by solid nanoparticles provides a diverse solvent microenvironment and enables to promote the phase transfer of reaction substrates/products in catalytic reactions, but the intrinsic role of solvent is still not clear. Herein, using benzyl alcohol (BA) as a model reactant, we demonstrate the nature of the water-promoted activity for alcohol oxidation over the Pd/MgAl-LDO catalyst. Depending on the water in the solvent, we observe different reactivities regarding the proportion of the water in the system. Kinetic isotope effects confirm the participation and positive effects of water for oxidation of BA. The water promotion effects are recognized and identified by the water vapor pulse adsorption coupled with temperature program desorption. Moreover, the adsorption behavior of BA or benzaldehyde at the interface of water and Pd/MgAl-LDO is also investigated by quasi-in-situ Raman spectroscopy. In addition, the mechanism of water-promoted alcohol oxidation is rationally proposed based on the Langmuir–Hinshelwood mechanism. The general applicability of the water promotion effects is further demonstrated over different supports and substrates, which well achieves excellent catalytic activity and selectivity in Pickering emulsion compared to that in the pure toluene system.

DOI: 10.1021/jacs.0c10618

Source: https://pubs.acs.org/doi/10.1021/jacs.0c10618