Electrochemical-driven nanoparticulate catalysis for highly efficient dechlorination of chlorinated environmental pollutant

Abstract

Devising new versatile catalytic systems for the efficient removal of chlorinated environmental pollutants from water has enormous implications for the environment and human health. By combining the advantages of both electrochemistry and nanotechnology, here we report a conceptually new, general approach of electrochemical-driven nanoparticulate catalysis for highly efficient dehalogenation of organic chlorides. By implementing this strategy, a continuous-flow removal of 4-chlorophenol was rapidly achieved with 100% of dechlorination efficiency within 120 min, and importantly, the dechlorination product phenol could further undergo hydrogenation reaction to completely transform into the mixture of cyclohexanone and cyclohexanol, significantly better than any reported catalytic methods. The essence of activation mechanism was attributed to the electric field-driven nanoparticles for activating the electrogenerated H2 to make numerous reactive species (e.g., atomic hydrogen) and for promoting direct electron transfer on the particles surface, thereby efficiently enabling their fast reactions with the adjacent pollutants. By conducting cyclic voltammetry and atomic-hydrogen quenching investigations, we first showed the direct and indirect reduction of chlorinated environmental pollutants in the voltammogram and provided a new evidence for the presence of these two mechanisms in the dehalogenation process. This work provides the first insight into electrochemical-driven nanoparticulate catalysis for dehalogenation of chlorinated environmental pollutants, showing a promising application for the remediation of these contaminants in water.