Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802-4400 USA.
Department of Chemistry, Trinity University, San Antonio, Texas 78212-7200, USA.
Nat Chem. 2018 Mar;10(3):268-274. doi: 10.1038/nchem.2911. Epub 2018 Jan 15.
Supported metal catalysts, which are composed of metal nanoparticles dispersed on metal oxides or other high-surface-area materials, are ubiquitous in industrially catalysed reactions. Identifying and characterizing the catalytic active sites on these materials still remains a substantial challenge, even though it is required to guide rational design of practical heterogeneous catalysts. Metal-support interactions have an enormous impact on the chemistry of the catalytic active site and can determine the optimum support for a reaction; however, few direct probes of these interactions are available. Here we show how benzyl alcohol oxidation Hammett studies can be used to characterize differences in the catalytic activity of Au nanoparticles hosted on various metal-oxide supports. We combine reactivity analysis with density functional theory calculations to demonstrate that the slope of experimental Hammett plots is affected by electron donation from the underlying oxide support to the Au particles.
负载型金属催化剂由金属纳米粒子分散在金属氧化物或其他高表面积材料上组成，在工业催化反应中无处不在。尽管需要指导实际多相催化剂的合理设计，但确定和描述这些材料上的催化活性位仍然是一个巨大的挑战。金属-载体相互作用对催化活性位的化学性质有巨大的影响，并可以决定反应的最佳载体；然而，目前可用的这种相互作用的直接探针很少。在这里，我们展示了如何使用苯甲醇氧化哈米特研究来表征负载在各种金属氧化物载体上的 Au 纳米粒子的催化活性差异。我们将反应性分析与密度泛函理论计算相结合，证明实验哈米特图的斜率受到来自底层氧化物载体向 Au 颗粒的电子供体的影响。
