Zhan Xiaohui, Wang He, Zhou Gaoyan, Chen Lei, Sun Yanping, Zhao Yue, Liu JunYan, Shi Huixiang
College of Environment & Resource Sciences, Zhejiang University, Hangzhou 310058, P. R. China.
ACS Appl Mater Interfaces. 2021 Mar 17;13(10):12118-12130. doi: 10.1021/acsami.1c00771. Epub 2021 Mar 3.
g-CN is a visible-light photocatalyst with a suitable band gap and good stability. Moreover, g-CN is considered to be earth-abundant, which makes it an appealing photocatalyst. However, due to its small specific surface area, low utilization of visible light, and high photogenerated electron-hole pair recombination rate, the photocatalytic activity of g-CN remains unsatisfactory. In this work, a highly efficient nonmetallic photocatalyst, ., g-CN doped with uracil (denoted U-CN) was successfully developed. Based on the various characterizations and calculations, it is shown that the triazine group in g-CN is replaced with the diazine group in uracil. This occurrence leads to the formation of a new electron-transfer pathway between triazine groups, which can promote the separation of photogenerated electrons and holes. Concurrently, due to the ultrathin structure of the as-prepared U-CN, the material possessed a larger specific surface area than pristine g-CN, which can provide more active sites. Furthermore, the transfer pathway between the electron and hole was also shortened, and the recombination of the electron and hole was inhibited. According to the results, an optimal hydrogen evolution rate of 31.7 mol h g was achieved by U-CN, which is 5.1 times higher as compared to that achieved by pristine g-CN (6.26 mol h g). For the photocatalytic degradation of rhodamine B, the reaction rate constant of U-CN (11.3 × 10 min) is about 5.5 times that of g-CN (2.07 × 10 min). Furthermore, the uracil-doped catalyst was also able to demonstrate good stability after five successive runs.
石墨相氮化碳（g-CN）是一种具有合适带隙和良好稳定性的可见光光催化剂。此外，g-CN被认为在地壳中储量丰富，这使其成为一种有吸引力的光催化剂。然而，由于其比表面积小、可见光利用率低以及光生电子-空穴对复合率高，g-CN的光催化活性仍然不尽人意。在这项工作中，一种高效的非金属光催化剂，即掺杂尿嘧啶的g-CN（表示为U-CN）被成功开发出来。基于各种表征和计算结果表明，g-CN中的三嗪基团被尿嘧啶中的二嗪基团所取代。这种情况导致在三嗪基团之间形成了一条新的电子转移途径，从而能够促进光生电子和空穴的分离。同时，由于所制备的U-CN具有超薄结构，该材料比原始的g-CN具有更大的比表面积，这可以提供更多的活性位点。此外，电子和空穴之间的转移途径也被缩短，电子和空穴的复合受到抑制。根据结果，U-CN实现了31.7 μmol h−1 g−1的最佳析氢速率，这是原始g-CN（6.26 μmol h−1 g−1）的5.1倍。对于罗丹明B的光催化降解，U-CN的反应速率常数（11.3×10−2 min−1）约为g-CN（2.07×10−2 min−1）的5.5倍。此外，掺杂尿嘧啶的催化剂在连续五次运行后也能够表现出良好的稳定性。
