In Situ Construction of SnS2@SnO2 Heterostructure for Photo‐Assisted Electrocatalysis of Oxygen Evolution Reaction

Abstract Photo‐assisted electrocatalysis has arisen as a promising approach for hydrogen generation by incorporating photocatalysts into electrocatalysts. 2D SnS 2 is a photocatalyst that absorbs visible light. However, the rapid recombination of photo‐generated electron‐hole pairs significantly reduces the overall photocatalytic efficiency of SnS 2 , limiting its practical application. Thus, this study prepares an in situ heterojunction SnS 2 @SnO 2 using a one‐step hydrothermal method. The degradation efficiency of methyl orange (MO) using SnS 2 @SnO 2 is measured, achieving a degradation rate of 92.75% within 1 h, which is 1.9 times higher than that of pure SnS 2 . Additionally, FeNiS/SnS 2 @SnO 2 is synthesized and exhibited significant improvements in the photo‐assisted oxygen evolution reaction (OER). It achieves an overpotential of 260 mV and a Tafel slope of 65.1 mV dec −1 at 10 mA cm −2 , showing reductions of 11.8% and 31.8%, respectively, compared to FeNiS alone. These enhancements highlight the strong photo‐response capability of SnS 2 @SnO 2 . Under the internal electric field of SnS 2 @SnO 2 , the photogenerated electrons in the conduction band of SnS 2 quickly move toward SnO 2 , facilitating efficient photocatalytic reactions. FeNiS, with a lower Fermi energy level (E F ), facilitates electron transfer from SnS 2 @SnO 2 and enhances OER performance by efficiently participating in the reaction. This study paves a new path for 2D photocatalyst materials.