CoMn₂O₄ embedded hollow activated carbon nanofibers as a novel peroxymonosulfate activator

Incorporation of cobalt-manganese oxide into the hollow carbonic framework is a prospective way to synthesize eco-friendly and efficient catalyst/adsorbent for advanced oxidation processes and wastewater treatments. Nonetheless, the complex fabrication process remains a major issue hindering the practical application of carbon-based bimetallic oxide catalyst. Herein, a facile and general method is developed to fabricate novel cobalt manganese oxide embedded hollow activated carbon nanofibers (Co_xMn_3−xO₄/HACNFs, x = 0,1,3) by using coaxial electrospinning technique and subsequent thermal treatment. Among the three Co_xMn_3−xO₄/HACNFs, CoMn₂O₄/HACNFs exhibited the best catalytic activity in PMS activation and Rhodamine B (RhB) degradation, due to the synergistic effect between spinel oxide and hybridized carbon network. Furthermore, HACNFs significantly improved the durability of CoMn₂O₄ by preventing metal leaching during PMS activation. A marginal decrease in the performance of used CoMn₂O₄/HACNFs was observed during five cycles, but the performance could be recovered by a simple calcination. A rational PMS activation mechanism of CoMn₂O₄/HACNFs was proposed. Benefiting from the unique structural features, CoMn₂O₄/HACNFs exhibited a superior adsorption and catalytic performance for RhB removal under continuous-flow reaction.