Integrating Bi2MoO6 nanoflakes into TiO2 photoanode for efficient charge separation in photoelectrochemical water splitting

Achieving highly effective water splitting based on conventional TiO2 photoanode is challenging due to its poor visible light response and low electrical conductivity. Herein, a Bi2MoO6/TiO2 heterojunction with a suitable band structure is constructed to broaden light absorption and accelerate oxidation kinetics. In particular, the highest photocurrent density (0.35 mA cm−2 at 1.23 V vs. RHE) of Bi2MoO6/TiO2 is 2.1 times higher than that of pristine TiO2. The integrated Bi2MoO6 nanoflakes enrich more reactive sites and charge transfer tunnels. The surface hole injection efficiency and electron lifetime of Bi2MoO6/TiO2 are 1.4 and 5.5 times larger than those of bare TiO2, respectively. Additionally, the activation energy and charge transfer resistance of Bi2MoO6/TiO2 electrodes are decreased remarkably, dramatically promoting the separation of electron-hole pairs. This work offers a novel strategy for TiO2-based heterojunction with great potential for application in photoelectrochemical water splitting. [Display omitted] •Bi2MoO6/TiO2 heterojunction prolongs electron lifetime and enlarges surface hole injection efficiency.•Bi2MoO6 nanoflakes broaden light absorption, enrich reactive sites, and provide charge transfer tunnels.•The charge transfer resistance of Bi2MoO6/TiO2 photoanode is decreased remarkably.•Twice enhancement on photocurrent density achieved by Bi2MoO6/TiO2 heterojunction.