Partial Oxidation of Methanol on MoO3 (010): A DFT and Microkinetic Study

Abstract

Methanol oxidation is employed as a probe reaction to evaluate the catalytic properties of the (010) facets of molybdenum trioxide (MoO3), a reducible oxide that exhibits a rich interplay of catalytic chemistry and structural transformations. The reaction mechanism is investigated with a combination of electronic structure calculations, using the BEEF-vdW and HSE06 functionals, and mean-field microkinetic modeling. Considered pathways include vacancy formation and oxidation, monomolecular dehydrogenation of methanol on reduced and nonreduced surfaces, bimolecular reactions between dehydrogenated intermediates, and precursor steps for hydrogen molybdenum phase (HyMoO3–x) formation. Methanol dissociation begins with C–H or O–H scission, with the O–H route found to be kinetically and thermodynamically preferred. Dehydrogenation of CH2O* to CHO* is slow in comparison to desorption, leading to complete selectivity toward CH2O. C–H scission of CH3O* and recombination of dissociated OH* to form H2O* are kinetica...