Surface State Trapping and Mobility Revealed by Junction Electrochemistry of Nano-Cr(2)O(3)
Cummings, C. Y., Attard, G. A., Mitchels, J. M. and Marken, F., 2012. Surface State Trapping and Mobility Revealed by Junction Electrochemistry of Nano-Cr(2)O(3). Australian Journal of Chemistry, 65 (1), pp. 65-71.
Related documents:This repository does not currently have the full-text of this item.
You may be able to access a copy if URLs are provided below. (Contact Author)
Hydrous chromium oxide nanoparticles (similar to 15 nm diameter) are assembled from a colloidal solution onto tin-doped indium oxide (ITO) substrates by layer-by-layer electrostatic deposition with aqueous carboxymethyl-cellulose sodium salt binder. Calcination produces purely inorganic mesoporous films (average thickness increase per layer of 1 nm) of chromia Cr(2)O(3). When immersed in aqueous carbonate buffer at pH 10 and investigated by cyclic voltammetry, a chemically reversible oxidation is observed because of a conductive layer at the chromia surface (formed during initial potential cycling). This is attributed to a surface Cr(III/IV) process. At more positive potentials higher oxidation states are accessible before film dissolution. The effects of film thickness and pH on voltammetric responses are studied. X-Ray photoelectron spectroscopy (XPS) evidence for higher chromium oxidation states is obtained. ITO junction experiments are employed to reveal surface conduction by Cr(III/IV) and Cr(IV/V) 'mobile surface states' and an estimate is obtained for the apparent Cr(III/IV) charge surface diffusion coefficient D(app) = 10(-13) m(2) s(-1). The junction experiment distinguishes mobile surface redox sites from energetically distinct deeper-sitting 'trapped states'.
|Creators||Cummings, C. Y., Attard, G. A., Mitchels, J. M. and Marken, F.|
|Departments||Faculty of Science > Chemistry|
Actions (login required)