In situ synthesis of MoO3/Ag/TiO2 nanotube arrays for enhancement of visible-light photoelectrochemical performance

Abstract A ternary composites of MoO 3 /Ag/TiO 2 nanotube arrays were synthesized by in-situ annealing of TiO 2 nanotube arrays impregnated with AgNO 3 over MoO 3 powders. During the annealing process, the crystallization of the TiO 2 nanotubes, the thermo-decomposition of AgNO 3 to Ag nanoparticles, and the sublimation of MoO 3 occur jointly. The photoelectrochemical measurements of the resultants indicate that MoO 3 /Ag/TiO 2 nanotube arrays present better photoelectrochemical properties compared with Ag/TiO 2 nanotube arrays and pristine TiO 2 nanotube arrays. Especially, the highest photocurrent and open circuit voltage are up to 21.29 μA/cm 2 and 0.058 V under visible light irradiation, whereas 1.77 and 3.87 times larger than those of TiO 2 nanotube arrays, respectively. Superior photoelectrochemical stability and larger photo-conversion efficiency of the ternary composites are also demonstrated. The improved photoelectrochemical properties are related to the close interfacial contact among MoO 3 , Ag, and TiO 2 as well as the surface plasma resonance of Ag in the ternary composites, which broaden the range of light response and enhance the efficiency of charge separation. This study provides a skillful solution to construct TiO 2 -based composite materials and demonstrates it is an unique architecture to promote the visible light driven photocatalytic application of TiO 2 .