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

In this study, copper phosphide (Cu 3 P) 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 O 2 − , were responsible for pollutant degradation. The Cu 3 P catalyst exhibited good stability and excellent anti-interference performance toward Cl − , NO 3 − , and HCO 3 − anions. The removal efficiency of Orange II remained close to 100%, even after five rounds of recycling reactions. The rapid catalytic mechanism of Cu 3 P is attributed to the dual-catalysis center in Cu 3 P (Cu and P) and simultaneous existence of three cycles ( Cu II  →  Cu III  →  Cu II , Cu I  →  Cu II  →  Cu I , and Cu δ+  →  Cu 1+δ+  → Cu δ+ ) on the surface and interior of Cu 3 P. This study sheds new light on the fabrication of high-performance heterogeneous catalysts to solve the environmental problems.