Electrocatalysis of H2 evolution on RuO2 + IrO2 mixed oxide electrodes

✍ Scribed by I.M. Kodintsev; S. Trasatti

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 512 KB
• Volume: 39
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(94)85168-9

✦ Synopsis

H, evolution from acid solutions has been studied on IrO, + RuO, electrodes over the whole oxide composition range. Kinetics has been investigated by means of cyclic voltammetry, quasistationary current-potential curves and reaction order determination. Results have shown that the Tafel slope for as-prepared electrodes is close to 40 mV and independent of oxide composition. The Tafel slope changes on electrodes aged by H, evolution: it varies from about 60mV for pure RuO, to about 20mV for pure IrO, . The anomalously low Tafel slope for IrO,-rich electrodes, and the apparent reaction order varying from 1 to ca. 2.5 have been interpreted on the basis of a single mechanism with different rate determining steps in which the back-reaction may have an appreciable effect due to oversaturation of the solution adlayer in the presence of quasi-equilibrium of the H, reaction in the pores of the oxide layer.