Manganese-Based Spinel Core–Shell Nanostructures for Efficient Electrocatalysis of 1,2-Dichloroethane

Electrocatalytic dechlorination continually attracts attention in dealing with chlorinated volatile organic compounds (CVOCs) due to its mild reaction conditions, economical, and environmental friendliness. Unfortunately, the electrocatalysts were reported to suffer from low dechlorination reactivity and selectivity, as well as unclear active sites. Here, we developed a core–shell NiMn2O4 (NiMn2O4–CS) via a facile solvothermal method as an efficient cathode catalyst for selective dechlorination of 1, 2-dichloroethane (1,2-DCA) into highly valuable ethylene. NiMn2O4–CS provided more active sites that could accelerate electron transfer efficiency and fix more intermediate species (*CH2CH2Cl). The as-prepared electrode showed significant current density (18.11 mA/cm2) at a potential of −2.75 V (vs SCE) and an ethylene Faradaic efficiency of 41%. Transfer coefficient α points out a concerted mechanism of dechlorination. The first-principles calculations indicated that the Ni atoms in octahedral sites of NiMn2O4 are the main active sites for 1,2-DCA dechlorination to ethylene. In addition, a remarkable charge transfer appeared between the intermediate of *CH2CH2Cl and the Nioct sites of NiMn2O4. This work provides reasonable ideas for the design of dechlorination electrocatalysts and the friendly transformation of CVOCs.