High-valent Cu(III)-mediated Fenton-like catalysis on WC engineered Cu2WS4 for low H2O2 consumption and pH-universal antibiotic degradation.

The sustainability of Fenton-like catalysts is generally impeded by sluggish metal redox cycling and the high consumption of hydrogen peroxide (H2O2). Herein, we report a facile ethanol-assisted solvothermal method to synthesize Cu2WS4 functionalized with WC bonds (denoted as e-Cu2WS4). Compared to its hydrothermally fabricated counterpart (w-Cu2WS4), e-Cu2WS4 exhibits remarkably enhanced catalytic performance for degrading tetracycline (TC) at an ultralow H2O2 concentration (1 mM). Experimental and theoretical analyses indicate that the in situ generated WC bonds act as efficient electron transfer bridges, enhancing bulk electrical conductivity and accelerating the rate-determining Cu(II)/Cu(I) cycling. Notably, the e-Cu2WS4/H2O2 system exhibits exceptional catalytic performance over a wide pH range (4.18-10.38) and in complex aqueous environments, attributed to a non-radical pathway mediated by high-valent Cu(III) species. Toxicity bioassays with zebrafish and mung beans indicate the conversion of TC into low-toxicity byproducts, a finding corroborated by computational toxicity predictions. This work presents the first application of Cu2WS4 in Fenton-like processes, revealing that electronic modulation induces a Cu(III)-dominated non-radical route for highly efficient and low-consumption wastewater remediation.