Density Functional Theory (DFT) and Kinetic Monte Carlo (KMC) Study of the Reaction Mechanism of Hydrogen Production from Methanol on ZnCu(111)

Abstract

Cu/ZnO-based catalysts have been widely used for methanol decomposition (MD), partial oxidation of methanol (POM), steam reforming of methanol (SRM), and oxidative steam reforming of methanol (OSRM). In this work, we systematically studied all possible reaction paths involved in MD, POM, SRM, and OSRM on ZnCu alloys (111) using density functional theory (DFT). On the basis of these results, Kinetic Monte Carlo (KMC) simulations show that the rate-limiting step of the four reactions is CH2O formation from CH3O dehydrogenation. The reaction pathway of MD occurs via the direct decomposition of CH3OH, and the main reaction pathways of POM and SRM occur via CH2OO and CH2OOH, respectively. There are two main reaction pathways of OSRM as follows: one occurs via CH2OO, whereas the other occurs via CH2OOH. Finally, according to the results of sensitivity analysis, some possible modifications to improve the CO2 selectivity and turnover frequency (TOF) of H2 for OSRM on Cu/ZnO-based catalysts are also presented. The...