Catalytic Properties of Copper and Palladium Single-Atom-Modified ZnO(100) in Methanol Steam Reforming: A Density Functional Theory Study

Abstract

Motivated by the exceptional catalytic performance of single-atom catalysts (SACs) in recent years, we investigated the stability and reaction mechanisms of single-atom Cu₁/ZnO and Pd₁/ZnO catalysts in methanol steam reforming (MSR) using periodic Density Functional Theory (DFT) calculations. Our results demonstrate that both metal atoms can be stably adsorbed at zinc vacancy sites on the ZnO(100) surface, with this stable adsorption resulting from the strong interaction between the metal atoms and lattice oxygen. Both catalysts follow similar reaction pathways: CH₃OH → CH₃O → HCHO → H₂COOH → HCOO → CO₂. Compared to the ZnO support and corresponding alloy catalysts, the single-atom catalysts exhibit lower activation barriers and higher catalytic activity. Additionally, we investigate the origin of the differences in catalytic reactivity between the single-atom catalysts and the ZnO support. This work provides new theoretical insights for the design of single-atom catalysts supported on oxide materials for MSR reactions.