Facile sol–gel fabrication of Cu/N–P-doped C nanocatalysts for peroxymonosulfate activation towards advanced oxidation of 4-nitrophenol

Abstract

Designing of heterogeneous catalysts is very important for activating peroxymonosulfate (PMS) in oxidative degradation of organic pollutants. In this work, Cu/N–P-doped C (Cu/N–P–C) was synthesized by a sol–gel method where the precursor was calcined in a N₂ atmosphere. The Cu/N–P–C prepared at 700 °C could activate PMS in oxidative degradation of 4-nitrophenol (4-NP) where 99.17% of 4-NP could be degraded in 4 minutes. The effects of the concentration of 4-NP, solution pH value, PMS dose, and catalyst dosage on the degradation of 4-NP were investigated, and the optimum pH value was determined to be 9. Electron paramagnetic resonance (EPR) and free radical quenching experiments showed that ¹O₂ was the primary reactive species, and ˙SO₄⁻ and ˙OH also contributed to the oxidation reaction, and a possible mechanism for this degradation was presented. The catalyst can be used five times in this oxidation system. Our study provides useful suggestions for designing catalysts with desirable activity.