Binary TiO2/RGO photocatalyst for enhanced degradation of phenol and its application in underground coal gasification wastewater treatment

• Published in: Optical materials 2021-10, Vol.120, p.111482, Article 111482
• Main Authors: Fan, Haiyang, Yi, Guiyun, Zhang, Zhengting, Zhang, Xiuxiu, Li, Peng, Zhang, Chuanxiang, Chen, Lunjian, Zhang, Yulong, Sun, Qi
• Format: Article
• Language: English
• Subjects: Binary nanocomposite; GC-MS; Photocatalytic degradation; Sol-anaerobic calcination; TOC; UCG wastewater
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2021.111482

In this work, we synthesized the TiO2/reduced graphene oxide (TiO2/RGO) binary nanohybrids through the sol-anaerobic calcination method, the TiO2 nanoparticles belonging to anatase type were evenly loaded on RGO surface in the form of Ti–O–C bond. The enhanced photocatalytic performance can be ascribed to the existence of RGO that can effectively promote the transfer of photo-induced electron-hole pairs to generate more hydroxyl radicals (·OH) and superoxide anion (O2·-) degrading phenol. The TiO2/RGO nanocomposite with weight ratio of RGO to TiO2 (37.0%–55.7%) had achieved maximum degradation of phenol from aqueous solution, and about 97.87% of phenol had been removed within 180 min under UV-light illumination. Through GC-MS tracking of phenol degradation process, it can be observed that long-chain intermediates will be generated, and these intermediates will eventually be degraded, confirming that phenol can be completely removed. Additionally, around 67% TOC of simulated underground coal gasification (UCG) wastewater can be removed after 10 h degradation using TiO2/RGO binary composites as photocatalysts. All these results demonstrate that the binary nanohybrids possess great potential for the organic contaminants destruction from the actual coal chemical wastewater. •The anatase-type TiO2 particles were uniformly anchored onto RGO nanosheets in the form of Ti–O–C covalent bond.•The optimized TiO2/RGO-2 nanohybrid can degrade 97.87% phenol from aqueous solution under weak acid condition.•The TOC removal rate of simulated underground coal gasification wastewater can reach 67%.•The superb performance is ascribed to the synergistic effect of ·OH, O2·−and h+.•The composite can be a potential candidate for the purification of actual coal chemical wastewater.