Enhanced photocatalytic hydrogen evolution by piezoelectric effects based on MoSe/Se-decorated CdS nanowire edge-on heterostructure.

The build-in electric field by the construction of heterojunction is one of the most promising strategies to suppress the recombination of photogenerated carriers. Here, we reported a piezo-photocatalytic system composed of Se-decorated CdS nanowires and few-layered edge-on MoSe nanosheets for efficient H generation by two-pot hydrothermal synthesis. The few-layered MoSe exposed abundant edge sites for hydrogen evolution reaction (HER). The activity of 20-MoSe/CdSSe (20-MS/CSS, with 20 mol% of MoSe loading) nanocomposite casted a remarkable photocatalytic HER performance, with a rate of 47.3 mmol h g. Moreover, MoSe nanosheets deformed to generate the piezoelectric polarization field under magnetic stirring, which rendered efficient separation of photogenerated carriers, resulting in a piezo-photocatalytic synergistic effect. As a result, the HER of 20-MS/CSS at 900 rpm for piezo-photocatalysis was 59.1 mmol h g, which was 1.25 times that of 20-MS/CSS for photocatalysis. Meanwhile, the photoelectrochemical measurements further visualized the piezo-photoelectric synergy. This study exposes a new way for utilizing mechanical energy to improve photocatalytic performance, and achieving high piezo-photocatalysis.