Hydrogenation engineering of bimetallic Ag–Cu-modified-titania photocatalysts for production of hydrogen

The efficacy of treatment with hydrogen and Ag-Cu co-deposition on TiO₂ photocatalysts has been investigated computationally and experimentally. The hydrogenated Ag-Cu with co-loaded TiO₂ (H:(Ag-Cu/TiO₂)) achieved a photoactivity about 110 times that of pristine TiO₂, which corresponds to a rate of 1.16 mmol h⁻¹ g⁻¹ for hydrogen generation. Soft X-ray spectra and quantum-chemical calculations indicate that the notable promotion of photoactivity on H:(Ag-Cu/TiO₂) is ascribable to the synergy between new electronic states and a lattice distortion. The soft X-ray absorption spectra (XAS) indicated that the TiO₆ octahedral symmetry and the Ti 3d- orbital orientation are significantly affected by the Ag-Cu decoration and the hydrogenation treatment. The mechanisms involved in this photocatalysis were studied with soft XAS in situ, which showed that the photoexcited electrons transfer from the bimetallic Ag-Cu to the TiO₂ conduction band as the photoresponse of this composite photocatalyst. The strategy of coupling hydrogenation with bimetallic Ag-Cu onto TiO₂-based photocatalysis provides a facile and promising solution to other environmental and energy applications.