CLASSICAL AND NEW APPROACHES FOR STUDYING THE ELECTROCATALYTIC ACTIVITY OF SILVER NANOPARTICLES FOR ENVIRONMENTAL APPLICATIONS

The electrochemical hydrodehalogenation of organic halocompounds at Ag-based cathodes represents a detoxification process of great interest [1] considering the impact of these molecules on the environment and on human health. In this context, this work presents the synthesis of different types of Ag nanoparticles (Ag-NP) as catalysts for the reduction of a model halogenated compound, CHCl3. The Ag-NP activity was studied with two electrochemical techniques: (i) cyclic voltammetry (CV), in which Ag-NP were supported onto a GC carbon electrode to study the reduction of a 0.01 M CHCl3 aqueous solution; (ii) scanning electrochemical microscopy (SECM) using the micropipette delivery-substrate collection (MD-SC) mode [2]: in this case the technique involved the use of glass micropipettes instead on metal tips for achieving a controlled delivery of CHCl3 in the solution, since CHCl3 is not an easy reagent for electrochemical generation. Finally, the possibility of increasing the silver activity by perturbing their surface structure via an electrochemical roughness process was also explored. The resulting enhanced activity is attributed to the formation of high-index surface planes. Financial supports from Università degli Studi di Milano (PUR 2009 Funds) and the Doctorate School in “Chemical Sciences and Technologies” of the Università degli Studi di Milano are gratefully acknowledged. C.L. is grateful to the University of Milan for a post-doc fellowship. 1. S. Rondinini, A. Vertova, "Electroreduction of Halogenated Organic Compounds", in Electrochemistry for the Environment, Ch. Comninellis, and G. Chen, (Eds.), Springer, 2010, DOI 10.1007/978-0-387-68318-8 2. C.-L. Lin, J. Rodríguez-López, A. J. Bard Anal. Chem. 2009, 81, 8868-8877