Carbon-Encapsulated NCO_4−β/C Hierarchical Nano-Microflowers for Electrocatalytic Dechlorination of Dichloromethane

Electrochemical dechlorination of dichloromethane (DCM) to high-value methane not only reduces carbon emission and environmental pollution but also alleviates energy shortages. In this study, a series of carbon-confined NiCo2O4−β/Cx (NCO4−β/Cx, x = 0, 0.5, 1, 2, 3) with hierarchical nano-microflower structures were successfully constructed via combining the hydrothermal method and dopamine in situ polymerization, which were utilized as electrocatalysts for electrochemical dechlorination of DCM. The as-prepared NCO4−β/C1 showed remarkable electrocatalytic dechlorination performance of DCM with a high methane selectivity of 87% and methane Faradaic efficiency of 17%, where the production rate of methane is up to 3538.25 μmol g–1 h–1 at −2.98 V (vs Ag/AgCl/Me4NCl). Notably, it could be experimentally proved that nickel cobaltite encapsulated in the carbon layer may accelerate the charge transfer and then build up the dechlorination activity. Additionally, two possible dichlorination mechanisms of DCM to methane are theoretically confirmed at the Ni active sites, which is proved by DFT calculations. This study presents promising ideas for developing efficacious dechlorination electrocatalysts and the efficient transformation of chlorinated volatile compounds (Cl-VOCs) to value-added methane in an environmentally benign manner.