Hydrogen Activation and Spillover on Anatase TiO2-Supported Ag Single-Atom Catalysts

Density functional theory (DFT) was used to examine the mechanisms of hydrogen activation and spillover on anatase TiO2-supported Ag single-atom catalysts. Stable structures of Ag were proposed on the (001) facet, considered a more catalytically active surface, and (101), a more stable facet. Surface oxygen vacancies (Ovac) were more favorably formed in the presence of Ag single atoms, reducing the energy of Ovac formation by 0.5 eV on (001) and 0.9 eV on (101). Ag single atoms adsorbed on TiO2 (001) and (101) surfaces promote H2 dissociative adsorption through a heterolytic mechanism, with an average activation barrier of 0.26 eV. Finally, reaction energies were calculated that corroborate experimental results of continuous hydrogen spillover from Ag to the TiO2 support.