Carbon nitride has drawn numerous eyes in the past decade, whereas the photocatalytic performance is significantly limited by its wide band-gap (∼2.7 eV for C₃N₄) simultaneously. Recently, C₃N₅ with narrower band-gap has been reported, however, a systematically investigation on its photoactivity for H₂ production has not been reported. The present work demonstrates the synthesis of C₃N₅ by thermal treatment of 3-amino-1,2,4-triazole, and the photocatalytic performance for H₂ production of C₃N₅ is investigated comprehensively. Photocatalytic H₂ production rate of C₃N₅ is ∼2.2 times higher than that of C₃N₄ with 1.0 wt% Pt as co-catalyst, and series of experiments are carried out to explore the behind elements accounting for the high photoactivity. Combining the results of DRS, PL and photocurrent, it is found that C₃N₅ possesses wider visible light absorption region, lower band-gap and quicker photogenerated e^-/h⁺ separation efficiency. Moreover, characterizations including in-situ DRIFTS are adopted to monitor the adsorption property of H₂O on C₃N₅, which plays a significant role in surface water reduction reaction, and higher amount of adsorbed H₂O molecules on C₃N₅ is confirmed. The present work exhibits new insights into the high photocatalytic performance of N-rich carbon nitride catalysts.

在过去的十年中，氮化碳吸引了无数人的目光，而光催化性能同时受到其宽带隙（C ₃ N ₄约为 2.7 eV ）的显着限制。最近，已经报道了具有更窄带隙的C ₃ N _{5 ，但是，尚未报道对其产生H 2}的光活性的系统研究。本工作展示了通过热处理3-氨基-1,2,4-三唑合成C ₃ N _{5 ，并全面研究了光催化产H 2}的C ₃ N ₅性能。光催化H _{2C 3} N ₅的产率是1.0 wt% Pt作为助催化剂的C ₃ N ₄的2.2倍，并进行了一系列实验来探索高光活性的背后元素。结合DRS、PL和光电流的结果，发现C ₃ N ₅具有较宽的可见光吸收区、较低的带隙和较快的光生e ^- /h ⁺分离效率。此外，采用包括原位漂移在内的表征来监测H ₂ O对C ₃ N _{5的吸附性能}，其在地表水还原反应中起重要作用，并且证实了C ₃ N _{5上吸附的H 2} O分子的量更高。目前的工作展示了对富氮氮化碳催化剂的高光催化性能的新见解。