Efficient photocatalytic hydrogen evolution over Cu3Mo2O9/TiO2 p-n heterojunction.

• Cu 3 Mo 2 O 9 /TiO 2 composite was prepared by a simple physical mixing method. • Cu 3 Mo 2 O 9 was first employed in photocatalytic hydrogen evolution from water splitting. • H 2 production rate of 10 wt. % Cu 3 Mo 2 O 9 /TiO 2 is 14.5 times higher than that of TiO 2. • The charge transfer between Cu 3 Mo 2 O 9 and TiO 2 follows the Type-Ⅱ route. The heterojunction formed by semiconductors with a matching electronic energy level structure can effectively promote charge transfer, thereby greatly improving the photocatalytic hydrogen production activity of the catalyst. Herein, the Cu 3 Mo 2 O 9 /TiO 2 hybrid was prepared via a simple mechanical mixing method. In the binary composite, the p-n heterojunction formed between Cu 3 Mo 2 O 9 and TiO 2 can favor the charge separation, resulting in excellent hydrogen production rate of 3401.9 μmol·g−1·h−1, it is 14.5-fold of pristine TiO 2. According to the optional and photoelectrochemical properties, it can be confirmed that Cu 3 Mo 2 O 9 plays a pivotal role in accelerating charge transfer and improving light absorption capacity of the composite. As a new type of photocatalyst, there is very limited information on Cu 3 Mo 2 O 9 for its application in photocatalytic hydrogen production. This work provides the possibility to expand application range of Cu 3 Mo 2 O 9 in energy conversion. [ABSTRACT FROM AUTHOR]