The hydrogen production rates from deionized water and 20% methanol solution, with or without the presence of Ta3N5, WO3, and the indirect Z-scheme Ta3N5/WO3, were investigated. Under irradiation of a 300 W Xe lamp, all of these three catalysts assisted hydrogen generation in deionized water. In the methanol solution, Ta3N5, and WO3 reduced the hydrogen generation, but Ta3N5/WO3 significantly enhanced the hydrogen production rate by seven times. Under visible light irradiation, the effects of the three catalysts are different from those under full spectrum irradiation. The mechanisms based on the competition of methanol decomposition and water reduction in the presence of catalyst under different irradiation conditions are proposed to explain the different hydrogen generation behaviors. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.