Theoretical new insights into hydrogen interaction with single-atom Zn- and co-doped copper metal catalysts

Abstract

Transition metal atoms, usually as active sites on the single-atom alloy catalysts, may access remarkable properties by tuning surface electronic structures of the matrix metals. Herein, we present a comprehensive study of the whole process of hydrogen interaction with the single-atom Zn- and Co-doped Cu(100) and Cu(111) surfaces by using density functional theory (DFT) calculations and microkinetic modelling. It is found that, the repulsive interaction of hydrogen and Zn dopant strongly increases the H2 dissociation barrier, the hydrogen adsorption energy and the surface diffusion/permeation barrier. In contrast, the Co-doped Cu surfaces yield some favorable reaction characters such as easy formation of subsurface hydrogen species. DFT-based microkinetic modelling further reveals that the coverage of surface and subsurface hydrogen on the Zn- and Co-doped Cu surfaces is strongly pressure-dependent. The formation of hot atoms involving subsurface hydrogen species observed on the Co-doped Cu catalysts under realistic reaction conditions may provide a new reaction pathway to accelerate surface hydrogenation reactions.