Enhancing the active site accessibility of cobalt-silica catalysts for improved Fenton-like performance

The narrow pore channels of cobalt-silica (CoSi) catalyst generated by conventional sol–gel process limited the active site accessibility. In this work, mesoporous CoSi catalysts containing highly dispersed Co sites were synthesized by a facile sol–gel derived soft-templating technique and tested for the Fenton-like oxidation of dyes and antibiotics. By controlling the concentration of triblock polymer Pluronic F127 template, the textural and chemical properties of CoSi catalysts were fine-tuned to improve the accessibility of their active sites. The CoSi catalyst achieved ∼ 96% removal of acid orange 7 (AO7) within 15 min using a low catalyst loading (50 mg L⁻¹) and H₂O₂ dosage (11 mM) at pH of 7–8. Moreover, thin-film CoSi coated on Al₂O₃ foam, as a monolithic catalyst prepared by the washcoating method, maintained high oxidation activity (∼99% removal for AO7) over 10 days, demonstrating excellent operational stability and process intensification for practical wastewater treatment applications.