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

A ternary composites of MoO3/Ag/TiO2 nanotube arrays were synthesized by in-situ annealing of TiO(2 )nanotube arrays impregnated with AgNO3 over MoO3 powders. During the annealing process, the crystallization of the TiO(2 )nanotubes, the thermodecomposition of AgNO3 to Ag nanoparticles, and the sublimation of MoO3 occur jointly. The photoelectrochemical measurements of the resultants indicate that MoO3/Ag/TiO2 nanotube arrays present better photoelectrochemical properties compared with Ag/TiO2 nanotube arrays and pristine TiO2 nanotube arrays. Especially, the highest photocurrent and open circuit voltage are up to 21.29 mu A/cm(2) and 0.058 V under visible light irradiation, whereas 1.77 and 3.87 times larger than those of TiO2 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 MoO3, Ag, and TiO2 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 TiO2-based composite materials and demonstrates it is an unique architecture to promote the visible light driven photocatalytic application of TiO2. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.