SnO₂@WS₂/p-Si Heterostructure Photocathode for Photoelectrochemical Hydrogen Production

This study reports an effective method to enhance the performance of photoelectrochemical (PEC) solar water reduction. We design and prepare a SnO2@WS2 NF heterostructure on p-Si that has better visible-light absorption as well as low recombination of electron–hole pairs. Consequently, a −3.5 mA cm–2 photocurrent density at 0 V versus a reversible hydrogen electrode is obtained using SnO2@WS2, and bare SnO2 and WS2 photocathodes exhibit values of −0.6 and −0.36 mA cm–2, respectively, showing the combined effects of these two materials for excellent hydrogen evolution reaction performance. Additionally, the photocurrent stability of the sample reveals the improved efficiency for the separation of generated charge carriers. Our study provides experimental and theoretical evidence that SnO2 doping improves the properties of WS2 for efficient PEC solar water reduction.