The rates of heterogeneous electrochemical reactions are governed, in part, by the degree of similarity between the potential energies of any electron donor–acceptor pair as well by the mechanism through which charge transfers between this pair at the electrode interface. Redox reactions tend to occur more rapidly and efficiently at noble metal electrodes, which is one reason why platinum electrodes commonly demonstrate lower overpotentials in electroanalytical measurements than lower-cost, energy-relevant electrode materials, such as carbon. In this study, we evaluate the electrochemical effect of modifying the surface of graphitic carbon electrodes with nanoscopic, conformal, electrolessly deposited ruthenia (RuO2). Because ruthenia is a platinum-group metal oxide that exhibits metallic conductivity, and was previously shown in nonaqueous electrolytes to mimic the fast electron-transfer character of platinum [1], it should serve to enhance the electrochemical electron-transfer kinetics of the underlying carbon electrode. The carbon electrodes in this study were prepared by chemical vapor deposition and the ruthenia colloids were deposited from nonaqueous solutions of ruthenium tetroxide gradually decomposed at &lt;0°C. These samples were calcined at various temperatures [T] up to 250°C in order to evaluate the increasing degree of crystallographic order in the as-deposited X-ray amorphous ruthenia on electrochemical reversibility. The response inner-sphere or outer-sphere redox probes at the RuO2@C[T] series was measured using cyclic voltammetry at scan rates between 5–10,000 mV s–1. In this poster, we will discuss our findings and the implications that they have for carbon-based electrodes in energy-relevant devices.

Modifying carbon electrodes to behave like precious metals

253rd National Meeting (2017)

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