Anchoring of Cu0 nanoparticles on the surface of magnetic separable high-entropy oxides for ultrafast catalytic degradation of sulfadiazine

A novel Cu 0 nanoparticle-anchored, magnetically separable spinel high-entropy catalyst ( Cu 0 NPs @ HEOs ) was synthesized via co-precipitation, freeze-drying, and high-temperature calcination for rapid catalytic degradation of sulfadiazine (SDZ) through H 2 O 2 activation. During the high-temperature calcination process, a fraction of Cu 0 nanoparticles precipitated and anchored on the catalyst surface, enhancing electron transfer at the interface while suppressing metal leaching. Cu 0 NPs @ HEOs system achieves a 99.34 % degradation rate for SDZ within 20 min—surpassing the 75.6 % degradation obtained using conventional medium- and low-entropy catalysts. Toxicity prediction software confirmed the low biotoxicity of degradation intermediates, ensuring environmental safety. The catalyst’s magnetic properties allowed for easy recovery using an external magnetic field, enabling reuse without performance degradation. Experimental characterization combined with density functional theory (DFT) calculations revealed that surface Cu sites acted as the primary active centers, effectively promoting H 2 O 2 adsorption and activation through electron transfer, accelerating ·OH generation. The main reactive species involved were ·OH, with minor contributions from O 2 – ·. Other metal sites provided electrons to sustain the high-entropy catalytic reaction. This study offers a new perspective on high-entropy material synthesis and highlights its potential in environmental remediation, especially for treating refractory organic pollutants.