Role variations of MnOx on monoclinic BiVO4 (110)/(040) facets for enhanced Photo-Fenton reactions
Haojie Wang, Xiaomei Liu, Di Wu, Yang Zhao, Ning Li, Yang Li, Xiaobin Fan, Qing Xia, Fengbao Zhang, Wenchao Peng
Abstract
Compared with traditional Fenton reaction, peroxymonosulfate based advanced oxidation processes (PMS-AOPs) are more effective to remove the organic pollutants in wastewater in a wider pH range. Herein, selective loading of MnO x on monoclinic BiVO 4 (110) or (040) facets were achieved by photo-deposition method with addition of different Mn precursors and electron/hole trapping agents. MnO x has good chemical catalysis activity for PMS activation, which can also enhance photogenerated charge separation, thus leading to enhanced activities than naked BiVO 4 . The BPA degradation reaction rate constants of MnO x (040)/BiVO 4 and MnO x (110)/BiVO 4 system are 0.245 min −1 and 0.116 min −1 , which are 6.45 and 3.05 times larger than that of naked BiVO 4 , respectively. The roles of MnO x on different facets are different, which will promote OER process on (110) facets and utilize the dissolved O 2 to produce O 2 •− and 1 O 2 more effectively on (040) facets. 1 O 2 is the dominated reactive oxidation species of MnO x (040)/BiVO 4 , while SO 4 •− and •OH play more important roles on MnO x (110)/BiVO 4 , which are proved by quenching experiments and chemical probe identifications, thus mechanism in MnO x /BiVO 4 -PMS-light system is proposed. The good degradation performance of MnO x (110)/BiVO 4 and MnO x (040)/BiVO 4 and mechanism theory may promote the application of photocatalysis in PMS based wastewater remediation.