C-Rich Graphitic Carbon Nitride with Cross Pore Channels: A Visible-Light-Driven Photocatalyst for Water Splitting
Shuo Zhao, Yuepeng Liu, Yanyun Wang, Liying Xie, Jiasheng Fang, Yiwei Zhang, Yuming Zhou, Shuping Zhuo
Abstract
Carbon nitride is found to be an outstanding metal-free photocatalyst for photocatalytic hydrogen evolution. However, carbon nitride suffers from insufficient light absorption and wide band gap, which limits the photocatalytic efficiency. Herein, we develop a carbon-rich graphitic carbon nitride with cross pore channels. The influence of rich carbon and porous structure on the optical and electrical properties of as-prepared carbon nitride is studied in detail. The carbon-rich carbon nitride exhibits larger surface area, enhanced light-harvesting ability, faster separation rate of photoinduced carriers through abundant carbon rings and narrower band gap than bulk CN. Especially, the carbon-rich carbon nitride displays a much higher hydrogen generation efficiency (551.5 μmol/h), which is approximately 117 times and 2.3 times higher than that of bulk carbon nitride obtained by the calcination of melamine (4.7 μmol/h) and pure CN (240.3 μmol/h), respectively. Moreover, an advanced H2 evolution rate of 3.7 μmol for CN-50 is obtained within 4 h without the addition of Pt cocatalysts, which is two times higher than that of pure CN. More importantly, excellent photostability with a negligible decrease in the catalytic ability for CN-50 can be achieved. This fabrication method can be extended to the design of catalysts with excellent photocatalytic activity for hydrogen generation, CO2 reduction, and many other processes.