P-Doped NiMn₂O₄ Hollow Tubular Nanofiber Spinel Composites for Electrocatalytic Dechlorination

Electrochemical degradation of dichloromethane (DCM) to produce chloromethane is a hopeful strategy for the remediation of chlorinated volatile organic compounds. However, developing high-efficiency electrocatalysts without a noble metal remains a challenge. Here, we successfully constructed P-doped NiMn2O4 hollow tubular nanofibers (P-x-NM-HTNFs) by the combination of an electrostatic spinning technique and a chemical vapor deposition technique, which were used as efficient dechlorination electrocatalysts. Physicochemical characterization and in situ characterization demonstrated that the unique hollow tubular nanostructures and P-doped structure can effectively accelerate charge transfer, expose more active sites, and optimize the adsorption capacity of the electrocatalyst for DCM. The experimental tests revealed that the P-doped electrocatalysts exhibited a remarkable electrocatalytic dechlorination performance, achieving a chloromethane production rate of 11665.46 mu mol g(-1) h(-1) at -3.03 V (vs Ag/AgCl/Me4NCl) for P-1.0-NM-HTNFs. In addition, the transfer coefficient alpha of 0.3 proved that the electrochemical degradation of DCM conforms to the mechanism of synergistic dissociation electron transfer. P-1.0-NM-HTNFs generate the adsorption atom H*, thus facilitating the dechlorination reaction. This work provides an idea for constructing manganese-spinel composite catalysts and producing chloromethane with high value added for DCM electrochemical dechlorination.