Overcoming Electrostatic Interaction via Strong Complexation for Highly Selective Reduction of CN− into N2

Limited by the electrostatic interaction, the oxidation reaction of cations at the anode and the reduction reaction of anions at the cathode in the electrocatalytic system nearly cannot be achieved. This study proposes a novel strategy to overcome electrostatic interaction via strong complexation, realizing the electrocatalytic reduction of cyanide (CN−) at the cathode and then converting the generated reduction products into nitrogen (N2) at the anode. Theoretical calculations and experimental results confirm that the polarization of the transition metal oxide cathodes under the electric field causes the strong chemisorption between CN− and cathode, inducing the preferential enrichment of CN− to the cathode. CN− is hydrogenated by atomic hydrogen at the cathode to methylamine/ammonia, which are further oxidized into N2 by free chlorine derived from the anode. This paper provides a new idea for realizing the unconventional and unrealizable reactions in the electrocatalytic system. Electrostatic interaction could severely inhibit the selective conversion of ions. This work proposes a strategy to overcome electrostatic interaction via strong complexation, realizing the preferential hydrogenation of cyanide at the cathode, and then oxidizing the reduction products into nitrogen at the anode. The controlled mass transfer of ions provides more possibilities for their selective conversion in the electrocatalytic system.