Silver is a well-known and largely studied electrocatalytic material for (hydro)dehalogenation reactions of organic halides, a class which includes several priority pollutants. Silver nanoparticles are particularly attractive since exhibit similar or even better performances than bulk silver allowing a significant reduction of precious metal loading. In this study the hydrodehalogenation of CHCl3 is selected as model reaction in order to evaluate the electrocatalytic activity of 2-15 nm silver nanoparticles. For the electrochemical characterization a versatile experimental setup was purportedly in-house designed and assembled that allows both cyclic voltammetry and electrolysis investigations. All the tests are performed in aqueous solution using a gas diffusion electrode as working cathode. The progressive conversion of gaseous trichloromethane to less chlorinated compounds is quantitatively evaluated in terms of concentration Cl- ions produced in the aqueous electrolyte solution. (C) 2014 Elsevier B.V. All rights reserved.