Insight into the catalytic performance of silver oxides towards peroxymonosulfate activation for pollutants degradation: Efficiency, mechanism and stability.

Silver-based materials have emerged as excellent catalysts for peroxymonosulfate (PMS) activation in wastewater pollutants degradation. However, the mechanism of pure silver oxides towards PMS activation remains insufficient. In this work, Ag 2 O and AgO were selected as typical silver oxides to detect the catalytic performance. AgO/PMS possessed higher activity for p-nitrophenol and other pollutants degradation than Ag 2 O/PMS. The stability experiment and structure changes characterized from XRD, FTIR, and XPS, as well as quenching research, demonstrated that SO 4 •− was the main free radical produced from the oxidation of Ag(I) to Ag(II) and reduction of Ag(II) to Ag(I) by PMS; meanwhile, the high valence Ag(II) could directly oxidize the pollutants, which was also contributable to the degradation. Compared with Ag 2 O, AgO exhibited better efficiency and recyclability. These results provide key mechanistic insights into silver oxides towards PMS activation. [Display omitted] • Silver based oxides Ag 2 O and AgO was used for PMS activation. • The two catalysts showed similar performance for PNP degradation. • The reusability and stability of AgO was much better than that of Ag 2 O. • SO 4 •− radicals were produced from the oxidation of Ag(I) by PMS. • The high active Ag(II) species contributed to the degradation process. [ABSTRACT FROM AUTHOR]