Cu-O-Fe boosts electronic transport for efficient peroxymonosulfate activation over a wide range of pH

The transition metal-oxygen-transition metal (TM1-O-TM2) structural bonds served as electron transport bridges facilitates the charge flow, which guided developing bimetallic activators for peroxymonosulfate (PMS). In this work, a bimetallic CuO/Fe₂O₃ heterojunction with Cu-O-Fe bond in a core-shell structure was designed. The configuration enhanced PMS activation over a wide range of pH, as demonstrated by the degradation of the model contaminant sulfamethoxazole (SMX), particularly under acid and alkaline condition (>95 % within 30 min). Mechanistic investigations were conducted under various pH conditions. Cu(III) and ¹O₂ were the dominant active species at acid and alkaline condition, respectively, confirmed by DFT calculations, characterizations and experiments. The degradation pathway of SMX was speculated by mass spectrometry combined with calculations. In addition, the substrate guidance mechanism which was verified by 6 kinds of emerging contaminants (ECs) further highlights the excellence of the surveyed system. The potential for practical application was suggested, attributed to the excellent performance in SMX removal from raw river water (98.7 %), tap water (100 %) and domestic sewage (86.7 %). This study provides new prospect into PMS activation by bimetallic heterojunctions attributing to electronic transport via TM1-O-TM2 bond, which is significant for treating ECs in water.