石墨相氮化碳形貌调控及其光催化性能研究

Morphology control of g-C3N4 with improved photocatalytic performance

石墨相氮化碳(g-CN)是一种能够利用太阳光中可见光的新型光催化剂,在解决能源和环境问题方面具有巨大的应用前景,但其光催化性能受限于比表面积小和光生载流子复合严重等本征不足。为了提高g-CN的光催化性能,以三聚氰胺和三聚氰酸为原料,通过超分子自组装、冷冻干燥前处理,结合高温缩聚法调控g-CN的形貌,制得一系列特殊形貌g-CN。研究发现,瓶状g-CN的比表面积增大、能带结构得到优化、氧化还原能力增强、光生载流子复合情况改善,从而提高了催化剂的光催化性能。选择光催化降解亚甲基蓝(MB)模拟废水研究瓶状g-CN的光催化性能,发现相比于传统的块状g-CN,光催化降解率由11.7%提升到97.1%;光催化降解速率常数提高12.3倍。提供了一种绿色、高效的g-CN形貌改性方法,对g-CN的改良优化以及实际应用具有一定的参考价值。

As a promising semiconductor photocatalyst with visible light response, graphite phase carbon nitride(g-CN) has great potential in solving energy and pollution issues.Unfortunately, the disadvantage, such as small specific surface area and high recombination rate of electron-hole generated during the photocatalysis, limit its practical application.Herein, to improve the photocatalysis performance, a series of g-CNwith various special morphology were synthesized.Through the supramolecular self-assembly method combined with one-step calcination process, the morphology of g-CNcan be controlled by changing the proportion of precursor.It was found that the specific surface area of the bottle-like g-CNwas increased, the recombination of photogenerated carriers was modified and the optimized band structure improved REDOX capacity.The methylene blue(MB) simulated wastewater was employed to evaluate the photocatalytic activity of a series of g-CNwith special morphology.Compared with that of traditional bulk g-CN,the photocatalytic degradation efficiency of bottle-like g-CNwas improved from 11.7% to 97.1%.Meanwhile, and the photocatalytic degradation rate constant of bottle-like g-CNincreased 12.3 times than that of bulk g-CN.This work provided green and efficient morphology modification method of g-CN,which had a certain reference value for the improvement and optimization of g-CNand practical application.