Interface-enhanced catalytic performance of TiO2-supported Cu and Au for dimethyl oxalate hydrogenation: A comparative microkinetic analysis

Abstract

The electronic structures of Cu-TiO2 and Au-TiO2 and their catalytic behaviors in the hydrogenation of dimethyl oxalate (DMO) have been studied by the stochastic surface walking-global neural network potential method, density functional theory calculation, and microkinetic analysis. Calculated results indicate that metal clusters on the pristine and oxygen-deficient TiO2 are mostly coordinated to O2c ions, and the defective surface may provide additional oxygen vacancies for Cu6 and Au6 cluster anchoring. It turns out that the interfacial Ti5c and Cuδ+/Auδ- ions provide adsorption and hydrogenation sites for the reaction intermediates with unsaturated O and C atoms, respectively. The turnover frequency for DMO consumption is much higher on Cu-TiO2 than on Au-TiO2, Cu(111), and Cu(211) at 443.15 K and 20 bar of total pressure. Given the satisfactory methyl glycolate (MG) selectivity, the Cu-TiO2 catalyst has the potential to act as an excellent catalyst for the selective MG production.