Novel carbon and defects co-modified g-C3N4 for highly efficient photocatalytic degradation of bisphenol A under visible light

• Published in: Journal of hazardous materials 2020-02, Vol.384, p.121323, Article 121323
• Main Authors: Wu, Ming, He, Xin, Jing, Binghua, Wang, Teng, Wang, Chengyin, Qin, Yanlin, Ao, Zhimin, Wang, Shaobin, An, Taicheng
• Format: Article
• Language: English
• Subjects: adsorption; Bisphenol A; Carbon and defects co-modification; carbon dioxide; carbon nitride; catalysts; Catalytic degradation; electrochemistry; g-C3N4; graphene; irradiation; melamine; mineralization; photocatalysis; photoluminescence; semiconductors; solar energy; superoxide anion; Visible light photocatalysis
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2019.121323

Carbon and defects co-modified carbon nitride (CxCN) was synthesized by a novel and facile method, shows porous structure, a lower bandgap and longer life of photogenerated electron-hole pairs for more fully use of solar-energy, and thus its photocatalytic degradation activity is about 22 times higher than that of pristine g-C3N4. [Display omitted] •Carbon and defects co-modified g-C3N4 (CxCN) was synthesized with a facile method.•Carbon and defects tune the band structure to promote utilization of solar energy.•CxCN structure is established by DFT calculation to explain related mechanism.•CxCN shows efficiently photocatalytic degradation of BPA under visible light. Graphite carbon nitride (g-C3N4, CN) is considered as a promising semiconductor for environmental catalysis. However, pure CN can not meet the requirements for actual applications due to its high recombination rate of photogenerated electron-hole pairs and a relatively large band gap preventing full utilization of solar energy. In this work, we report synthesis of a novel carbon and defects co-modified g-C3N4 (CxCN) by calcination of melamine activated by oxalic. This new catalyst CxCN has porous structure with much higher surface areas compared with pristine CN. UV–vis analysis and DFT calculations show that CxCN has a lower bandgap for enhancing visible light adsorption compared with CN. Photoluminescence (PL) and photoelectrochemical analyses show that CxCN has a low recombination rate of photogenerated electron-hole pairs, which improves the utilization of solar energy. As a result, CxCN samples show high efficiency for the degradation of bisphenol A (BPA) under visible light irradiation, where the best catalyst of CxCN (C1.0CN) samples shows about 22 times higher photocatalytic degradation rate than that of CN. Moreover, C1.0CN shows high mineralization rate and can degrade BPA into CO2 and H2O by the generated active species, like superoxide radicals (O2−) and holes (h+).