Synergistic enhancement of photoelectrochemical water splitting using core/shell ZnO/Bi2S3 heterostructures

Abstract

Abstract Solar energy can be harnessed to generate hydrogen via photoelectrochemical (PEC) water splitting, providing a clean, renewable energy pathway. This study developed core/shell ZnO/Bi 2 S 3 heterostructures via electrodeposition and successive ionic layer adsorption and reaction (SILAR), and systematically investigated their structural, optical, and electrochemical properties. UV-Visible analysis revealed that ZnO/Bi 2 S 3 composites absorb strongly across the UV and visible regions, thereby enhancing light harvesting compared to bare ZnO. Coating ZnO nanorods with Bi 2 S 3 significantly improved PEC response, with Mott–Schottky plots confirming n-type behavior. Under simulated sunlight, the ZnO/Bi 2 S 3 photoanode produced a photocurrent density of 3.74 mA/cm 2 at 0.9 V vs. RHE, about 4 times that of pristine ZnO. Charge-transfer dynamics and hydrogen-evolution mechanisms were explored, revealing that the core/shell structure enhances light absorption, facilitates charge separation, and improves photocatalytic performance. These results highlight ZnO/Bi 2 S 3 as a promising photoanode material for PEC water splitting and sustainable hydrogen generation.