Stability, Durability, and Reusability Assessment of Nanostructured ZnO Photoelectrodes for Sustainable Solar Hydrogen Generation

Photoelectrochemical (PEC) water splitting using semiconductor photoelectrodes has emerged as a promising pathway for sustainable solar hydrogen generation. While significant progress has been achieved in enhancing photocurrent density and band gap engineering of ZnO-based photoelectrodes, their long-term operational stability, durability, and reusability remain critical challenges that limit real-world deployment. The present study systematically investigates the stability, photocorrosion resistance, and reusability of nanostructured ZnO photoelectrodes under prolonged PEC operation. Nanostructured ZnO photoelectrodes were evaluated under continuous illumination and repeated operational cycles to assess structural integrity, photocurrent retention, and hydrogen generation sustainability. Long-term chronoamperometric measurements revealed stable photocurrent behavior with minimal degradation over extended operation. Structural and morphological analyses before and after PEC testing confirmed the preservation of crystalline phase and surface architecture, indicating strong resistance against photocorrosion. Reusability studies demonstrated consistent photoresponse over multiple operational cycles, highlighting the durability of the ZnO nanostructures.