In situ anchoring of high-entropy alloy nanoparticles on nitrogen-doped graphene: Multimetallic synergy and N-mediated electronic modulation for enhanced peroxymonosulfate activation and wastewater treatment

Peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs) generate highly oxidizing radicals for efficient and eco-friendly degradation of organic pollutants. In this study, a composite catalyst of nitrogen-doped graphene (NGr) supported high-entropy alloy nanoparticles (MnFeCoCuZn, HEAs), denoted as HEAs/NGr, was synthesized via high-temperature calcination combined with metal salt impregnation. The synergistic effect of the high-entropy stability of HEAs and the NGr support minimized metal ion leaching (<0.0383 mg/L). The HEAs/NGr catalyst (100 mg/L) achieved 99.5 % degradation of Rhodamine B (RhB, 100 mg/L) within 5 min, with a rate constant of 1.0581 min −1 . The formation of M–N bonds between HEAs and NGr modulated the electronic structure of the composite, as evidenced by electrochemical tests showing enhanced interfacial electron transfer kinetics and PMS activation capability. Quenching experiments and EPR results confirmed that RhB degradation primarily followed a non-radical pathway dominated by singlet oxygen ( 1 O 2 ). The HEAs/NGr catalyst exhibited excellent tolerance to coexisting anions and maintained >94.3 % degradation efficiency across a pH range of 3.0–11.0. LC-MS and ECOSAR toxicity analysis confirmed effective RhB degradation and significantly reduced ecological toxicity of intermediates. This work deepens the understanding of multi-atomic synergy mechanisms and provides theoretical and practical insights for carbon-based water purification technologies.