Defect-rich carbon based bimetallic oxides with abundant oxygen vacancies as highly active catalysts for enhanced 4-aminobenzoic acid ethyl ester (ABEE) degradation toward peroxymonosulfate activation

Abstract

Meeting with severe environmental problems, highly efficient, environmental friendly and multiple reusable catalysts are demanding to develop. In this work, carbon based bimetallic oxides with oxygen vacancies were prepared toward peroxymonosulfate (PMS) activation for 4-aminobenzoic acid ethyl ester (ABEE) degradation. Among different molar ratios of ferrous ions and manganese ion, Fe1Mn1-Fe NC appeared optimum catalytic performance. The degradation of ABEE should contain free radical pathway and non-free radical pathway. All of sulfate radical, hydroxyl radical, superoxide radical and singlet oxygen were responsible for efficient degradation and mineralization of ABEE. Lattice oxygen was the main reactive site for ABEE degradation. Electron transport provided good synergistic redox reaction between Fe and Mn and promoted lattice oxygen released. New proposed pathway for ABEE degradation included electrophilic and radical addition, hydrogen abstraction reaction and diazotization. This work is expected to provide rational design of bimetallic materials with oxygen vacancy for in-situ environmental remediation.