Bc. Shah et Ac. Hillier, Imaging the reactivity of electro-oxidation catalysts with the scanning electrochemical microscope, J ELCHEM SO, 147(8), 2000, pp. 3043-3048
We describe an application of the scanning electrochemical microscope that
utilizes tip-sample feedback to characterize the reactivity of electro-oxid
ation catalysts. The kinetics of hydrogen oxidation are probed at a platinu
m electrode as a function of applied potential in aqueous sulfuric acid sol
ution. Tip-sample feedback generates a tip response that reflects the rate
of hydrogen oxidation at the substrate. The ability to directly measure the
rate constant for hydrogen oxidation is, subsequently, used to perform rea
ctivity mapping of heterogeneous electrodes consisting of catalytic and non
catalytic domains. Differences in reaction kinetics clearly distinguish sur
face composition variations based upon their reactivity toward hydrogen oxi
dation and illustrate the capability of this technique as a screening tool
in the design of electrocatalysis. Further experiments investigating the ox
idation of methanol illustrate the ability to characterize complex multiste
p reactions. (C) 2000 The Electrochemical Society. All rights reserved.