用于光电化学分解水的三维贯通纳米多孔Ta₃N₅薄膜: 厚度调控与稳定性研究

Solar-driven photoelectrochemical (PEC) water splitting is a promising technology for sustainable hydrogen production, which relies on the development of efficient and stable photoanodes for water oxidation reaction. The thickness and microstructure of semiconductor films are generally crucial to their PEC properties. Herein, three-dimensional (3D) interconnected nanoporous Ta₃N₅ film photoanodes with controlled thickness were successfully fabricated via galvanostatic anodization and NH₃ nitridation. The porous Ta₃N₅ nanoarchitectures (NAs) of 900 nm in thickness showed the highest PEC performance due to the optimal light-harvesting and charge separation. Compared with the hole-induced photocorrosion, the electrochemical oxidation at high anodic potentials resulted in severer performance degradation of Ta₃N₅. Although the surface oxide layer on deteriorated Ta₃N₅ photoanodes could be removed by NH₃ re-treatment, the PEC performance was only partially recovered. As an alternative, anchoring a dual-layer Co(OH)_x/CoOOH co-catalyst shell on the porous Ta₃N₅ NAs demonstrated substantially enhanced PEC performance and stability. Overall, this work provides reference to controllably fabricate 3D nanoporous Ta₃N₅-based photoanodes for efficient and stable PEC water splitting via optimizing the light absorption, hole extraction, charge separation and utilization. [Figure not available: see fulltext.]