Development of Novel Perovskite-Like Oxide Photocatalyst LiCuTa3O9 with Dual Functions of Water Reduction and Oxidation under Visible Light Irradiation

Development of new visible-light-responsive materials is highly desirable in photocatalysis. Here, a novel oxide material LiCuTa3O9 (LCTO) with a characteristic perovskite-like structure, exhibiting a visible light absorption edge of approximate to 500 nm due to the hybridization of Cu 3d and O 2p orbitals, is reported. The structure of the as-obtained LCTO is experimentally characterized and theoretically simulated. UV-vis diffuse reflectance spectroscopy, Mott-Schottky, and density functional theory calculation results show that the LCTO is an n-type semiconductor with bandgap of approximate to 2.48 eV and exhibits suitable conduction band and valence band positions of approximate to-0.45 and 2.03 eV vs reversible hydrogen electrode, respectively. Based on initial optimization of preparative conditions and loading of cocatalysts, the as-modified LCTO sample can drive both water reduction and oxidation half reactions in the presence of corresponding sacrificial reagents under visible light irradiation (lambda >= 420 nm), demonstrating its promising application in solar water splitting. The dual functional features of LCTO render it a promising photocatalyst for one-step overall water splitting to produce hydrogen. In addition, the unobvious structural change of the LCTO photocatalyst during the reaction and repeated runs of the photocatalytic H-2 evolution reaction demonstrate its good photochemical stability.