Boundary effect of Ag/TiO2 on catalytic H2O splitting for H2 production: A theoretical account

Abstract

Ag supported on TiO2 reveals advantages in photocatalytic H2O splitting due to its synergistic effects for promoting the e−/h+ separation. The structural and electronic characteristics of Ag/TiO2, as well as adsorption and splitting of H2O on different sites, were investigated employing the density functional theory calculations. The analysis of density of states and electrons densities evidenced the electron transfer and hybrid between Ag and TiO2. The boundary was especially reactive toward the target species being the most active site, and thus electrons could be transferred to the adsorbate through the supported Ag atoms, leading to the generation of Schottky barrier, which inhibited the recombination of photogenerated electron-hole pairs. The O–H bond cleavage with the Ea of 2.18 eV was the rate-determining step for H2 production on the Ag/TiO2 boundary. Fukui functions indicated the outermost Ag cluster site on Ag/TiO2 boundary exhibited high electron transferability and H2 production tendency.