Fernández Estefanía, Boronat Mercedes, Corma Avelino
Instituto de Tecnología Química, Universitat Politècnica de València - Consejo Superior de Investigaciones Científicas, Av de los Naranjos s/n, Valencia 46022, Spain.
Phys Chem Chem Phys. 2022 Feb 16;24(7):4504-4514. doi: 10.1039/d1cp05166k.
The mechanism of the CO oxidation reaction catalysed by planar Cu, three dimensional (3D) Cu, and 3D Cu clusters is theoretically investigated at the B3PW91/Def2TZVP level. All three clusters are able to catalyse the reaction with similar activation energies for the rate determining step, about 16-18 kcal mol, but with remarkable differences in the reaction mechanism depending on cluster morphology. Thus, for 3D Cu and Cu clusters, O dissociation is the first step of the mechanism, followed by two consecutive CO + O reaction steps, the second one being rate determining. In contrast, on planar Cu the reaction starts with the formation of an OOCO intermediate in what constitutes the rate determining step. The O-O bond is broken in a second step, releasing the first CO and leaving one bi-coordinately adsorbed O atom which reacts with CO following an Eley-Rideal mechanism with a low activation energy, in contrast to the higher barriers obtained for this step on 3D clusters.
在B3PW91/Def2TZVP水平上，从理论上研究了平面铜、三维（3D）铜和3D铜簇催化的CO氧化反应机理。所有这三种簇都能够催化该反应，速率决定步骤的活化能相似，约为16 - 18千卡/摩尔，但根据簇的形态不同，反应机理存在显著差异。因此，对于3D铜和铜簇，O解离是反应机理的第一步，随后是两个连续的CO + O反应步骤，第二步是速率决定步骤。相比之下，在平面铜上，反应从形成OOCO中间体开始，这是速率决定步骤。第二步中O - O键断裂，释放出第一个CO，并留下一个双配位吸附的O原子，该O原子按照Eley - Rideal机理与CO反应，活化能较低，这与在3D簇上该步骤获得的较高势垒形成对比。
