The semiconductor/electrolyte interface plays important roles in defining the performance of photocatalysts but is poorly studied. Here, we report a surprising observation that unique reactions at this interface under photo-electrochemical (PEC) conditions lead to unusual performance enhancement of Ta₃N₅ for solar water oxidation reactions. The enhancement was only observed when Co(OH)₂ was introduced as a water oxidation co-catalyst. Illumination and positive bias were also critical to the enhancement. It was proposed that O^• radical formation induced by illumination results in the formation of Ta-O-Co bonds, which exhibit less severe Fermi-level pinning when compared with Ta-O-Ta bonds that are more commonly observed on bare Ta₃N₅ under normal PEC conditions. When a high-performance oxygen evolution catalyst such as cobalt phosphate (Co-Pi) was added to the Ta₃N₅/Co(OH)₂ system, high photocurrent densities and good stability were achieved simultaneously.

半导体/电解质界面在定义光催化剂的性能中起重要作用，但研究不足。在这里，我们报告了一个令人惊讶的观察结果，即在光电化学（PEC）条件下在该界面处发生的独特反应导致Ta ₃ N ₅在太阳能水氧化反应中的性能得到非同寻常的增强。仅当引入Co（OH）₂作为水氧化助催化剂时才能观察到这种增强。照明和正偏差对于增强效果也很关键。有人提出，由照明引起的O ^•自由基的形成导致Ta-O-Co键的形成，与在裸Ta上更常见的Ta-O-Ta键相比，其显示的费米能级钉扎不那么严重在正常PEC条件下为₃ N ₅。将高性能的析氧催化剂（例如磷酸钴（Co-Pi））添加到Ta ₃ N ₅ / Co（OH）₂系统中时，可以同时实现高光电流密度和良好的稳定性。