Bismuth oxide cocatalyst and copper oxide sensitizer in Cu2O/TiO2/Bi2O3 ternary photocatalyst for efficient hydrogen production under solar light irradiation

Abstract

A novel Cu2O/TiO2/Bi2O3 ternary nanocomposite was prepared, in which copper oxide improves the visible light absorption of Ti0(2) and bismuth oxide improves electron-hole separation. The ternary composite exhibited extended absorption in the visible region, as determined by UV-Vis diffuse reflectance spectroscopy. Highresolution transmission electron microscopy images showed close contact among the individual semiconductor oxides in the ternary Cu2O/TiO2/Bi2O3 nanocomposite. Improved charge carrier separation and transport were observed in the Cu2O/TiO2/Bi2O3 ternary composite using electrochemical impedance spectroscopy and photocurrent analysis. TiO2 modified with bismuth and copper oxides showed exceptional photocatalytic activity for hydrogen production under natural solar light. With optimum bismuth and copper oxide loadings, the Cu2O/ TiO2/Bi2O3 ternary nanocomposite exhibited an H-2 production (3678 mu mol/h) 35 times higher than that of bare TiO2 (105 mu mol/h). The synergistic effect of improved visible absorption and minimal recombination was responsible for the enhanced performance of the as-synthesized ternary nanocomposite.