Efficient organics heterogeneous degradation by spinel CuFe2O4 supported porous carbon nitride catalyst: Multiple electron transfer pathways for reactive oxygen species generation

Abstract

Facilitating reactive oxygen species (ROS) generation is an effective way to promote the heterogeneous catalytic efficiency for organics removal. However, the metal leaching in metal-based catalysts and the low activity of non-metallic materials restrict ROS production. In this work, the purpose was achieved by loading a small amount of spinel CuFe2O4 onto porous carbon nitride substrate. The synthesized CuFe2O4@O–CN composite first to activate peroxymonosulfate (PMS), which produce a plenty of ROS (•OH, SO4•− and 1O2) for organics removal, leading to highly oxidation for diverse organics. Through the comparative analysis of the surface composition before and after reaction, we found that the interface multi-electron transfer routs, including surface Cu(II)/Cu(I), Fe(III)/Fe(II) and their cross interaction, participated in the redox cycle, giving rise to the rapid and massive production of ROS, so that DMPO and TEMP were instantly oxidized in electron paramagnetic resonance (ESR) detection. Importantly, the carrier of porous O–CN, which acted as the electron transfer mediator, not only favors PMS adsorption via surface –OH, but also facilitates the conversion between different metal species. As a result, the CuFe2O4@O–CN/PMS system can remove 99.1% BPA and achieve 52.6% mineralization under optimized conditions. Thus, this study not only sheds light on the tailored design of heterogeneous catalyst for organics removal and elucidates the interfacial catalytic mechanisms for PMS activation.