Engineering Reusable Sponge of Cobalt Heterostructures for Highly Efficient Organic Pollutants Degradation via Peroxymonosulfate Activation

Abstract The rational 3D design of affordable cobalt heterostructures with tunable catalytic properties and water phase functionality is highly desirable for advanced oxidation applications. Herein, we demonstrate a new and scalable approach based on thermal‐induced phase separation chemistry that allows controllable in situ growth of cobalt oxide (Co₃O₄) nanoflowers onto a self‐standing polymer sponge. Detailed characterization revealed that the Co₃O₄ nanoflowers were uniformly and tightly attached on a mesoporous polymeric network with a surface area of 230.0 m²/g and excellent mechanical stability. The catalytic performance of the sponge‐like catalyst was evaluated by degradation of model organic compounds (i. e., acid orange 7, AO7) under various operational conditions. The results indicate that complete color removal of AO7 can be achieved in <2 min, with a >84% TOC mineralization and negligible cobalt leaching under optimal conditions. The SP‐50/PMS system could also effectively remove a broad range of compounds like antibiotic tetracycline, acid orange 52 (typical fluorescent azo‐dye), and rhodamine B (a typical basic dye). Time‐resolved electron paramagnetic resonance (EPR) data revealed that SO₄^.− and OH^.− were the primary oxidative species. Overall results exemplified the advantages of high‐performance sponge catalyst for the remediation of organic pollutants from water environment.