Nonuniform temperature dependence of the reactivity of disordered VO(x)/kappa-Al2O3(001) surfaces: a density functional theory based Monte Carlo study

J Chem Phys. 2008 Dec 14;129(22):224710. doi: 10.1063/1.3021290.

Abstract

Periodic density functional theory (DFT) calculations concerning VO(x)/kappa-Al(2)O(3)(001) surfaces are used for parametrizing Monte Carlo simulations performed on a mesoscopic scale surface sample (41.95x48.80 nm(2)). New structural and chemical information are then obtained that are not accessible from DFT calculations: segregation, short- and long-range ordering, and the effect of the temperature on the reducibility. The reducibility of the surface is investigated for locating chemical potential regions where the catalyst is especially reactive for oxidation reactions. Comparison with the V(2)O(5)(001) surface at catalytic conditions (800 K, 1 bar) is performed. The reducibility exhibits an unexpectedly strong temperature dependence.