Synergistic Inhibition of Oxide Formation in Oxidation Catalysis: A First-Principles Kinetic Monte Carlo Study of NO + CO Oxidation at Pd(100)

Abstract

Oxide formation under oxygen-rich reaction conditions has independently been reported for both CO oxidation and NO oxidation with Pd single-crystal model catalysts. We present a first-principles kinetic Monte Carlo study addressing the simultaneous occurrence of both reactions at Pd(100) exposed to CO- and NO-containing feeds. Even in most oxygen-rich feeds, very small amounts of NO are found to reduce the surface oxygen coverage well below the level required to induce oxide formation. Even though NO and CO compete for the same surface sites and surface oxygen, the ongoing NO oxidation reactions furthermore lead to a partially strong enhancement of the CO oxidation activity. This highlights synergistic effects of multicomponent gas feeds on both surface composition and catalytic activity that cannot be captured, nor extrapolated from prevalent studies focusing on individual reactions.