Electrochemical study of TiO2 modified with silver nanoparticles upon CO2 reduction

• Published in: Journal of applied electrochemistry Vol. 44; no. 5; pp. 675 - 682
• Main Authors: Cueto-Gómez, Luisa F., Garcia-Gómez, Nora A., Mosqueda, Hugo A., Sánchez, Eduardo M.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-05-2014
• Subjects: Chemistry; Chemistry and Materials Science; Electrochemistry; Industrial Chemistry/Chemical Engineering; Physical Chemistry; Research Article; Electrochemical reduction; Transmission line model; Titanium dioxide; Carbon dioxide; Electrochemical impedance spectroscopy
• ISSN: 0021-891X; 1572-8838
• DOI: 10.1007/s10800-014-0677-z

A systematic cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) study on titanium dioxide (TiO
2
) and silver–TiO
2
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
2
compared to bare TiO
2
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
2
surface states was identified and separated from (a) silver reduction, (b) electronic transport on TiO
2
, and (c) charge transfer on TiO
2
and Ag surfaces. The Ag–electrolyte interface impedance has considerably lower values than the TiO
2
–electrolyte interface, suggesting that the silver particles may be considered as favorable reaction sites for the electrochemical reduction of water and carbon dioxide.