Copper phosphide: A dual-catalysis-center catalyst for the efficient activation of peroxydisulfate and degradation of Orange II

Abstract

In this study, copper phosphide (Cu3P) was used as a heterogeneous catalyst for peroxydisulfate (PDS) activation and Orange II degradation. This catalyst functions over a broad pH range, from 3.0 to 9.0 and the degradation rate of Orange II is 95.2% at 15 min under optimal conditions. The rapid degradation kinetics can be described by the Behnajady-Modirshahla-Ghanbery (BMG) equation. Sulfate radical, the main reactive oxidizing species, along with OH and O2−, were responsible for pollutant degradation. The Cu3P catalyst exhibited good stability and excellent anti-interference performance toward Cl−, NO3−, and HCO3− anions. The removal efficiency of Orange II remained close to 100%, even after five rounds of recycling reactions. The rapid catalytic mechanism of Cu3P is attributed to the dual-catalysis center in Cu3P (Cu and P) and simultaneous existence of three cycles (CuII → CuIII → CuII, CuI → CuII → CuI, and Cuδ+ → Cu1+δ+ → Cuδ+) on the surface and interior of Cu3P. This study sheds new light on the fabrication of high-performance heterogeneous catalysts to solve the environmental problems.