Three-dimensional P-doped porous g-C3N4 nanosheets as an efficient metal-free photocatalyst for visible-light photocatalytic degradation of Rhodamine B model pollutant

• Published in: Journal of the Taiwan Institute of Chemical Engineers Vol. 114; pp. 249 - 262
• Main Authors: Li, Zesheng, Chen, Qianying, Lin, Qiachun, Chen, Ying, Liao, Xichun, Yu, Huiqing, Yu, Changlin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2020
• Subjects: Graphitic carbon nitride; Mesoporous structure; P doping; Photocatalysis; Rhodamine B; Rhodamine B; Mesoporous structure; Photocatalysis; P doping; Graphitic carbon nitride
• DOI: 10.1016/j.jtice.2020.09.019
• ISSN: 1876-1070

•Newly P-doped porous g-C3N4 nanosheets with in-plane mesopores are successfully prepared.•Successive air thermal oxidation and P element doping method is developed for the first time.•High specific surface area (202.9 cm2 g−1) and desirable P content (0.87 At. %) were obtained.•Our P-doped porous g-C3N4 nanosheets showed excellent visible-light photocatalytic activity.•Mesopores and P doping can offer an efficient separation of photoproduced electron-hole pairs. As a typical metal-free photocatalyst, graphitic carbon nitride (g-C3N4) has attracted great attention for photocatalytic degradation of various organic pollutants. In this study, three-dimensional (3-D) phosphorus (P)-doped porous g-C3N4 nanosheets were prepared successfully via the thermal oxidation and element doping associated method. Abundant in-plane mesopores (from 2 nm to 50 nm), high specific surface area (202.9 cm2 g−1) and desirable P content (0.87%) were obtained for this 3-D P-doped porous g-C3N4 nanosheets. Taking Rhodamine B as a model pollutant, the photocatalytic properties of this 3-D P-doped porous g-C3N4 nanosheets photocatalyst were investigated, and the mechanism of photocatalytic degradation was also proposed. The 3-D P-doped porous g-C3N4 nanosheets showed the much enhanced visible-light photocatalytic activity, with Rhodamine B degradation ratio of 99.5% and a kinetic reaction rate constant of 0.120 min−1, compared to porous g-C3N4 nanosheets (58.2% and 0.031 min−1). The catalytic mechanism analysis shows that the active radicals of •OH and •O2− have strong oxidizing property, which can quickly decompose target organic dyes. The mesoporous structure and high P content of doping endowed photocatalyst with abundant active sites, high conductivity, and efficient separation of photoproduced electron-hole pairs.