Fine-tuning inverse metal-support interaction boosts electrochemical transformation of methanol into formaldehyde based on density functional theory

Abstract

Different from traditional metal-support heterogenous catalysts, inverse heterogeneous catalysts, in which the surface of metal is decorated by metal oxide, have recently attracted increasing interests owing to the unique interfacial effect and electronic structure. However, a deep insight into the effect of metal-oxide interaction on the catalytic performance still remains a great challenge. In our work, an inverse hematite/palladium (Fe2O3/Pd) hybrid nanostructure, i.e., the active Fe2O3 ultrathin oxide layers partially covering on the surface of Pd nanoparticles (NPs), exhibited superior electrocatalytic performance towards methanol oxidation reaction (MOR) as compared to the bare Pd NPs based on density functional theory calculation. The charge could transfer from Pd to Fe2O3 driven by the built-in potential at the interface of Pd and Fe2O3, which favors the downshift of d band center of Pd. With the assistance of interfacial hydroxyl OH*, the cleavage of OH and CH in CH3OH could take place much easily with lower barrier energy on Fe2O3/Pd than that on pure Pd via two electrons transferring reaction pathways. Our results highlight that the synergy of Pd and Fe2O3 at the interface could facilitate the electrochemical transformation of methanol into formaldehyde assisted with interfacial hydroxyl OH*.