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 (O-vac) were more favorably formed in the presence of Ag single atoms, reducing the energy of O-vac formation by 0.5 eV on (001) and 0.9 eV on (101). Ag single atoms adsorbed on TiO2 (001) and (101) surfaces promote H-2 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