Electrochemical study of TiO modified with silver nanoparticles upon CO reduction

A systematic cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) study on titanium dioxide (TiO) and silver-TiO surfaces was performed in order to decouple electrochemical reduction processes of carbon dioxide in aqueous solutions. CV studies indicate cathodic current increase on Ag-TiO compared to bare TiO surfaces. An equivalent circuit based on transmission line model was applied in order to adjust EIS data, and a modification of this model was made to account for Ag particle interaction with the electrolyte solution. Electrochemical processes were then decoupled upon applied potential where the role of TiO surface states was identified and separated from (a) silver reduction, (b) electronic transport on TiO, and (c) charge transfer on TiO and Ag surfaces. The Ag-electrolyte interface impedance has considerably lower values than the TiO-electrolyte interface, suggesting that the silver particles may be considered as favorable reaction sites for the electrochemical reduction of water and carbon dioxide. © 2014 Springer Science+Business Media Dordrecht.