Synergistic Cu mesh-CuO supported Ag nanoparticles for enhanced 2-nitrophenol reduction

Efficient and recyclable catalysts for the reduction of nitrophenols into value-added aminophenols are highly desirable for environmental remediation, yet conventional powder-based catalysts often suffer from aggregation, catalyst loss, and poor recyclability. Herein, we report a facile hydrothermal strategy to construct an immobilized ternary AgNPs@CuO@Cu catalyst, in which Ag nanoparticles (25–75 nm) and CuO particles (200–400 nm) are uniformly anchored onto a conductive copper mesh. This integrated Cu-CuO-Ag architecture not only enables convenient catalyst recovery but also provides intimate interfacial contact among metallic Ag, semiconducting CuO, and the conductive Cu substrate, thereby promoting synergistic effects and efficient charge transport. Structural characterizations (XRD, SEM) confirm the coexistence of crystalline Ag and CuO with strong interfacial coupling. The optimized catalyst exhibits outstanding activity for the NaBH₄-assisted reduction of 2-nitrophenol, achieving 93.0% conversion within 20 min at room temperature and following pseudo-first-order kinetics with a high apparent rate constant (k = 0.12997 min −1 ). Notably, an unusual negative activation energy (-22.5 kJ mol −1 ) is observed, indicating an adsorption–desorption-controlled kinetic regime that deviates from conventional electron-transfer-limited mechanisms typically reported for powder catalysts. Radical quenching experiments further reveal that superoxide radicals (•O₂ - ) and direct electrons dominate the reduction pathway, while •OH radicals and holes play auxiliary roles. This work demonstrates that copper mesh-supported AgNPs@CuO catalysts provide an effective and structurally stable platform for nitrophenol remediation and offer new insights into radical-assisted reduction mechanisms with abnormal kinetic behavior. • A ternary AgNPs@CuO@Cu catalyst was synthesized via a facile hydrothermal method. • AgNPs (25-75 nm) and CuO (200-400 nm) were uniformly dispersed on Cu mesh. • More than 93% reduction of 2-nitrophenol was achieved within 20 min at room temperature. • Pseudo-first-order kinetics with k = 0.12997 min - 1 and Ea = -22.5 kJ.mol - 1 were obtained. • Synergistic effects of Ag, CuO, and Cu mesh improved reusability and remediation potential.