Vitamin B₁₂-Functionalized NiMn₂O₄ Spinel: A Promising Bioinspired Electrocatalyst for Dechlorination in the Aqueous Phase

Electrochemical selective dechlorination of dichloromethane (DCM) to methane and chloromethane is a promising and sustainable strategy to remove halogenated contaminants and generate clean energy. In this work, we present an approach wherein vitamin B12 (VB12) is immobilized on the surface of NiMn2O4 hollow tubular nanofibers (NM-HTNFs) for electrocatalytic DCM reduction dechlorination in the aqueous phase system. This bioinspired catalytic system, which integrates a natural molecule, demonstrates remarkable yields of organic products. Remarkably, a total organic product yield of 127.845 mmol g–1 h–1 (methane, 49.017 mmol g–1 h–1; chloromethane, 69.740 mmol g–1 h–1; ethylene, 9.097 mmol g–1 h–1) at −1.60 V (vs Ag/AgCl) was achieved, and an impressive methane Faradaic efficiency up to 26.78% was achieved. Experimental findings were supported by in situ adsorption FTIR spectroscopy that shed light on a synergistic effect of NM-HTNFs and VB12, facilitating the adsorption ability of DCM and the charge transfer rate, further enhancing the carbon–chlorine (C–Cl) bond scission. It dramatically improved the reductive performance of DCM dechlorination. This work is expected to provide a bioinspired way where naturally abundant VB12 has been taken full advantage of for the efficient transformation of DCM to high-value-added products.