Enhanced electrocatalytic hydrogen evolution performance of 2D few-layer WS2 nanosheets via piezoelectric effects

Two-dimensional transition metal disulfides are considered a great candidate for non-noble metal catalyst because of their abundant reserves and excellent electrochemical activity in hydrogen evolution reaction (HER). Herein, two-dimensional (2D) few-layer WS 2 nanosheets were synthesized via a facile liquid phase stripping technique. The piezoelectricity of the synthesized WS 2 nanosheets was verified by piezoelectric force microscope (PFM) and used to promote the piezo-catalytic hydrogen generation, where the piezoelectric charges generated under ultrasound vibration are utilized for hydrogen evolution. Moreover, the effect of various mechanical vibration conditions on the piezo-catalytic HER of WS 2 was also discussed. The results show that under the same overpotential, the hydrogen production rate with ultrasound vibration (40 kHz, 40 W) is 6 times higher and the impedance is 4 times lower than that without ultrasound. The catalytic efficiency of WS 2 can be significantly increased through this method, which paves the way towards non-noble metal HER catalysts to produce hydrogen with aid of piezoelectricity.