Liang Juan, Jing Chengjun, Wang Jiarong, Men Yupawang
College of Architecture and Environment, Sichuan University, Chengdu 610065, China.
Institute for Disaster Management and Reconstruction, Sichuan University, Chengdu 610065, China.
Molecules. 2021 Nov 22;26(22):7054. doi: 10.3390/molecules26227054.
Graphitic carbon nitride (g-CN) photocatalysts were synthesized via a one-step pyrolysis process using melamine, dicyandiamide, thiourea, and urea as precursors. The obtained g-CN materials exhibited a significantly different performance for the photocatalytic reduction of Cr(VI) under white light irradiation, which is attributed to the altered structure and occupancies surface groups. The urea-derived g-CN with nanosheet morphology, large specific surface area, and high occupancies of surface amine groups exhibited superior photocatalytic activity. The nanosheet morphology and large surface area facilitated the separation and transmission of charge, while the high occupancies of surface amine groups promoted the formation of hydrogen adsorption atomic centers which were beneficial to Cr(VI) reduction. Moreover, the possible reduction pathway of Cr(VI) to Cr(III) over the urea-derived g-CN was proposed and the reduction process was mainly initiated by a direct reduction of photogenerated electrons.
以三聚氰胺、双氰胺、硫脲和尿素为前驱体，通过一步热解过程合成了石墨相氮化碳（g-CN）光催化剂。所制备的g-CN材料在白光照射下对光催化还原Cr(VI)表现出显著不同的性能，这归因于其结构和表面基团占有率的改变。具有纳米片形态、大比表面积和高表面胺基占有率的尿素衍生g-CN表现出优异的光催化活性。纳米片形态和大表面积促进了电荷的分离和传输，而高表面胺基占有率促进了有利于Cr(VI)还原的氢吸附原子中心的形成。此外，还提出了尿素衍生g-CN上Cr(VI)还原为Cr(III)的可能途径，还原过程主要由光生电子的直接还原引发。
