Establishing an efficient way via TiO2/MXene catalyst for photoelectro activating PMS degradation of BPA

Abstract

In this system, a highly-exposed TiO2 photoanode was prepared as an effectively photoelectrocatalyst peroxymonosulfate (PMS) activator. Especially, we realize the highly-exposed TiO2 grown on negatively charged MXene nanosheet which could provide dual active sites for stimulating PMS. The catalysts were characterized by XRD, XPS, SEM, UV–vis, Raman, TEM, and BET. The specific surface area for highly-exposed TiO2 (S-400) is 10 times than Bulk catalyst (B-400), which is displayed in the BET result. The experimental results show that high exposure catalyst has excellent photoelectric activation performance. The degradation efficiency of the PEC + PMS system was 2.94 times higher than the EC + PMS and 2.76 times higher than the PC + PMS process. Compare with free PMS (1.36˚A), PMS adsorbed at the photoanode interface has a high bond angle (2.85˚A) easily to decompose into strong oxidizing SO4−. The electrochemical characterization results demonstrated that the highly-exposed TiO2 had a higher separation rate of photogenerated carriers. From quenching experiments, the holes (h+) contributed 80 % to BPA degradation in PEC + PMS system, the contribution order of other active radicals was O2−>SO4−>OH. It will help improving the control of the optimal free radical ratio. The probable mechanism and pathway of BPA degradation were suggested e− reacts with PMS and other substances to generate radicals. The research offers a new strategy for the effective activation about PMS to oxidation of the refractory organics. Besides, the results provide useful theoretical guidance for the development of new high-activity materials.