Noble metals enhanced catalytic activity of anatase TiO2 for hydrogen evolution reaction

Although anatase TiO2 is a promising candidate for hydrogen evolution reaction in acidic media, the application of TiO2 is hindered by the poor electrical transport and reactivity of active sites. Here, we report on the hydrogen occupied mechanism, noble metal-doped effect and influence of noble metal on the hydrogen evolution activity of TiO2 by using the first-principles approach. We find that hydrogen prefers to occupy the tetrahedral interstice site because of the strongly localized hybridization between hydrogen and TiO2. Importantly, those noble metals can improve the electronic transport between the valence band and the conduction band near the Fermi level. Ag-doping and Au-doing are more thermodynamically stable than that of Pt-doping, Pd-doping and Ru-doping. In comparison with other noble metals, we find that Ag-doping is beneficial to enhance the hydrogen evolution reaction activity of TiO2 because hydrogenated Ag-doping weakens the electronic transfer between Ti-3d state and O-2p state near the Fermi level. Finally, our work indicates that Ag-doping is a promising TiO2 HER catalyst. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.