Photosensitive WS₂/ZnO Nano-Heterostructure-Based Electrocatalysts for Hydrogen Evolution Reaction

Two-dimensional transition-metal dichalcogenides (2D-TMDCs) have shown great promise for sustainable energy production via electrocatalytic, photocatalytic, and photovoltaic activities. Here, we report the WS2/ZnO (WZO) nano-heterostructures with optimized materials properties for high-performance photoelectrocatalytic activity. WZO nano-heterostructures have shown faster electrocatalytic hydrogen evolution reaction (HER) compared to pristine WS2 and ZnO owing to the reduced charge transfer resistance and enhanced active area of the catalysts. HER activity has been found to be stable for chrono-amperometry of 25 h and cyclic voltammetry of 2000 cycles. The catalyst has shown visible light-sensitive catalytic activity and a significantly reduced over potential of −182 mV versus RHE (reversible hydrogen electrode) at 10 mA/cm2. Additionally, a self-powered and fast photodetection ability with a responsivity of 6.7 mA/W, stability upto 1600 s, and response time of 80 ms has been reported. The maximum photoresponsivity of 1.34 A/W was realized at −250 mV versus RHE. Besides, present findings report the importance of dominating pyroelectricity for photoswitching. Overall, the present findings explored the photo-sensitive 2D-TMDCs as an alternative of noble metals in electrocatalytic activity for clean energy production.