Volume 172, 2014

Nanodiamond surface redox chemistry: influence of physicochemical properties on catalytic processes

Abstract

Modification of an electrode with an immobilised layer of nanodiamond is found to significantly enhance the recorded currents for reversible oxidation of ferrocene methanol (FcMeOH). Current enhancement is related to nanodiamond diameter, with enhancement increasing in the order 1000 nm < 250 nm < 100 nm < 10 nm < 5 nm. We attribute the current enhancement to two catalytic processes: i) electron transfer between the solution redox species and redox-active groups on the nanodiamond surface; ii) electron transfer mediated by FcMeOH+ adsorbed onto the nanodiamond surface. The first process is pH dependent as it depends on nanodiamond surface functionalities for which electron transfer is coupled to proton transfer. The adsorption-mediated process is observed most readily at slow scan rates and is due to self-exchange between adsorbed FcMeOH+ and FcMeOH in solution. FcMeOH+ has a strong electrostatic affinity for the nanodiamond surface, as confirmed by in situ infrared (IR) experiments.

Associated articles

Article information

Article type
Paper
Submitted
17 Mar 2014
Accepted
18 Mar 2014
First published
20 Mar 2014
This article is Open Access
Creative Commons BY license

Faraday Discuss., 2014,172, 349-364

Author version available

Nanodiamond surface redox chemistry: influence of physicochemical properties on catalytic processes

T. S. Varley, M. Hirani, G. Harrison and K. B. Holt, Faraday Discuss., 2014, 172, 349 DOI: 10.1039/C4FD00041B

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