Graphitic Carbon Nitride Codoped with Sulfur and Yttrium for Efficient Visible-Light Photocatalytic Performance

The correlation of electronic band structure and photocatalytic performance of graphitic carbon nitride (g-C3N4) provides important perspectives for understanding the catalytic mechanism and developing efficient catalysts. Herein, sulfur and yttrium co-doped graphite carbon nitride (Y/S-CN) was prepared by a facile calcination process of melamine, 2-thiobarbituric acid, and yttrium nitrate hexahydrate at elevated temperatures. The hydrogen evolution rate of the optimal 0.01Y/S-CN photocatalyst reached 19.2 mu mol/h, which was about 16 times that of pure CN and 3.51 times that of S-CN. This outstanding photocatalytic performance originates from that doping. Sulfur and yttrium into the g-C3N4 lattice improved the separation and migration of electron-hole pairs, narrowed the band gap, and increased visible light harvest. DFT calculation demonstrated that doping S and Y in the g-C3N4 lattice increased the separation of the HOMO and LUMO and narrowed the band gap of g-C3N4. This work could provide a facile synthesis of modified CN and promising insights into understanding the mechanism for efficient visible-light photocatalytic performance.