Preparation of Silver-Modified Nickel Foams by Galvanic Displacement and Their Use as Cathodes for the Reductive Dechlorination of Herbicides

New 3D electrodes are prepared and tested in reductive herbicide dechlorination as the first step of an environmental remediation process. Commercial nickel foams are modified through the spontaneous deposition of silver nanoparticles. Some of the solutions of Ag+ ions employed in the galvanic displacement reactions contain complexing agents, such as thiosulfate or thiocyanate, and a capping agent, polyvinylpyrrolidone (PVP), which influences the morphology and growth kinetics of the silver deposits. Modified foams are used as cathodes for the reductive dechlorination of AlachlorTM, a common chloroacetanilide herbicide, in a series of tests that confirm the catalytic activity of silver. Electrodes prepared in a thiosulfate solution containing PVP allow extensive reduction of AlachlorTM to give deschloroalachlor as the only dechlorinated product.