Comparable catalytic activity of a low-cost catalyst IrO2/TiO2 for methane conversion – A density functional theory study

Abstract

Designing an efficient, low-cost catalyst is an important objective in the catalytic conversion of methane into value-added products that would be useful in many technological applications. Although IrO2 can activate C–H bonds at mild temperature and have excellent catalytic activity towards C–C coupling reactions, the high cost hinders its deployment. Herein, we propose IrO2 supported on TiO2 surface (IrO2/TiO2) and investigate its catalytic activity towards the methane dehydrogenation and the possibility of C–C coupling reactions with the help of density functional theory (DFT) calculations. Its catalytic performance is compared with that of a pure IrO2 surface. We find that the IrO2/TiO2 surface possesses similar adsorption characteristics of CH4 to the pure IrO2 surface. Our kinetic results indicate that the proposed catalyst exhibits similar enhanced catalytic activity towards methane activation and its successive dehydrogenation and C-C coupling reactions to that of pure IrO2 surface. We believe that methane can be more likely activated over the catalyst of one layer IrO2 supported on TiO2 at low temperatures, and it shows similar performances in thermodynamics like high-cost pure IrO2.