Remarkably enhanced photocatalytic H2 evolution via construction of Ti0.5Ru0.5O2/TiO2(B)/TiO2(A) three-phase-junctions

Abstract TiO2 is an important material used in photocatalytic H2 evolution. Here nanosheets with a Ti0.5Ru0.5O2/TiO2(B)/TiO2(A) three-phase-junctions, composed of solid solution rutile phase Ti0.5Ru0.5O2, bronze phase TiO2(B), and anatase phase TiO2(A), are constructed via a hydrothermal method and subsequent calcination. At the optimal calcination temperature of 350 °C, the highest H2 evolution rate reaches 27.817 mmol∙g−1∙h−1 at 25 °C, which is further increased up to 62.357 mmol∙g−1∙h−1 at 70 °C by synergistic photothermal catalysis. The photocatalytic activity of the optimized catalyst was further enhanced by loading with Pt as a co-catalyst. It is found that, in addition to helping charge separation, migration, and inhibiting the charge recombination, the three-phase-junctions structure is a key to present strong oxidation and reduction ability. Ti0.5Ru0.5O2 solid solution has excellent co-catalytic ability, much better than Ru oxide, metallic Ru, as well as Pt. It works as hole acceptor, accelerating the generation and quench of photo induced peroxyl radicals, and thus significantly enhancing the H2 generation rate.