ELECTROCHEMICAL TECHNOLOGIES: ADVANCED ELECTRODE MATERIALS FOR ENVIRONMENTAL APPLICATION

An investigation on a new class on electrocatalytic materials for the electroreduction of organic halides is presented and discussed. The electrocatalysts are based on silver nanoparticles (Ag_NP and Ag_NC), ad hoc synthesised by two different synthetic path (Polyol assisted and Wet chemical reduction). The obtained nanoparticles are then supported on carbon black (pre-treated or untreated) (20% or 10% loading) for further characterisation and use. The electrocatalytic properties of the Ag_NP/carbon and Ag_NC/carbon composites towards the dehalogenation of halocompounds are tested by cyclic voltammetry and by preparative electrolysis. The hydrodehalogenation of trichloromethane, is selected as a model reaction, because of its relevance for the detoxification of wastes. The voltammetric characterisation is performed both in an aqueous and non aqueous solution, supporting the composites on cavity microelectrodes. Gas-diffusion electrodes (GDE) based on the most promising Ag_NP composite – and, for reference, on a commercial Ag/C oxygen reduction electrocatalyst – are then tested in an electrolytic process for the progressive conversion of gaseous trichloromethane to less chlorinated compounds, and ultimately to methane.