Rationally designed hierarchical 2D CdS/2D FePS ₃ heterojunctions for boosted photocatalytic hydrogen production

Abstract Two‐dimensional (2D) nanomaterials have emerged as highly efficient co‐catalysts in the field of photocatalytic water splitting, due to their distinct physicochemical features. Herein, a novel 2D nanomaterial, ultrathin FePS 3 nanosheets, is prepared by an ultrasound‐assisted delamination process in organic solvent, followed by the in situ construction of CdS nanosheet/FePS 3 nanosheet hierarchical heterojunction via the solvothermal method. It is notable that the designed CdS/FePS 3 photocatalyst demonstrates an efficient hydrogen‐producing performance up to 7565 μmol g −1 h −1 for hydrogen production reaction (HER) under visible‐light illumination, which is almost 8 times higher than that of bulk CdS. The enhancement in HER performance is attributed to the synergy of accelerated interfacial charge transfer, high specific surface area, and extended visible‐light absorption originating from as‐synthesized conductive few‐layer FePS 3 nanosheets. Furthermore, the charge transfer pathway of the constructed 2D CdS/2D FePS 3 heterojunction is unveiled by in situ atomic force microscopy with Kelvin probe force microscopy (AFM‐KPFM), in situ X‐ray photoelectron spectroscopy (XPS), and photoelectrochemical measurements. This study offers new insight into the rational design and controllable synthesis of FePS 3 ‐based composite photocatalytic systems for efficient photocatalytic hydrogen production.