Sun Lidong, Li Yu, Feng Wei
School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China.
Key Laboratory of Advanced Ceramics and Machining Technology Ministry of Education, Tianjin 300072, China.
Nanomaterials (Basel). 2021 Dec 23;12(1):37. doi: 10.3390/nano12010037.
Graphitic carbon nitride (g-CN) has attracted much attention because of its potential for application in solar energy conservation. However, the photocatalytic activity of g-CN is limited by the rapidly photogenerated carrier recombination and insufficient solar adsorption. Herein, fluorinated g-CN (F-g-CN) nanosheets are synthesized through the reaction with F/N mixed gas directly. The structural characterizations and theoretical calculations reveal that fluorination introduces N vacancy defects, structural distortion and covalent C-F bonds in the interstitial space simultaneously, which lead to mesopore formation, vacancy generation and electronic structure modification. Therefore, the photocatalytic activity of F-g-CN for H evolution under visible irradiation is 11.6 times higher than that of pristine g-CN because of the enlarged specific area, enhanced light harvesting and accelerated photogenerated charge separation after fluorination. These results show that direct treatment with F gas is a feasible and promising strategy for modulating the texture and configuration of g-CN-based semiconductors to drastically enhance the photocatalytic H evolution process.
石墨相氮化碳（g-CN）因其在太阳能储存方面的应用潜力而备受关注。然而，g-CN的光催化活性受到光生载流子快速复合以及太阳能吸收不足的限制。在此，通过直接与F/N混合气体反应合成了氟化g-CN（F-g-CN）纳米片。结构表征和理论计算表明，氟化同时在间隙空间引入了N空位缺陷、结构畸变和共价C-F键，这导致了中孔形成、空位产生和电子结构改性。因此，由于氟化后比表面积增大、光捕获增强以及光生电荷分离加速，F-g-CN在可见光照射下的析氢光催化活性比原始g-CN高11.6倍。这些结果表明，用F气体直接处理是一种可行且有前景的策略，可用于调节g-CN基半导体的织构和构型，从而大幅增强光催化析氢过程。
