Highly dispersed cobalt nanoclusters on dolomite: A low-cost catalytic platform for enhanced peroxymonosulfate activation toward sustainable 5-Fluorouracil degradation

Peroxymonosulfate (PMS)-based advanced oxidation processes exhibit significant potential for the degradation of organic pollutants. In this study, a highly dispersed cobalt nanoclusters supported on dolomite (Co@Dol) was successfully synthesized via a simple water-bath deposition–calcination method, enabling efficient activation of PMS for the degradation of 5-fluorouracil (5-FLU). The results demonstrate that Co nanoclusters are uniformly anchored on the dolomite surface via Co-O unsaturated coordination, achieving exceptional electron transfer and catalytic degradation efficiency through synergistic Ca/Mg interactions. With a low Co loading of 0.58 wt%, a removal rate of 98.39% for 5-FLU was achieved, while the Co leaching concentration remained as low as 0.327 mg/L. Characterization and mechanistic studies reveal that the pre-decomposition of dolomite yields a loosely structured cationic framework, which not only stabilizes the Co active sites but also enhances the dissociation of PMS into SO₄^•− radicals via surface alkalinity. The abundant oxygen vacancies significantly promote the Co²⁺/Co³⁺ redox cycling, ensuring that the degradation efficiency of 5-FLU remains above 95% after five cycles. This work presents a novel strategy for designing cost-effective cobalt-based catalysts supported by natural mineral substrates.