Transient characteristics of methanol electrooxidation on Pt and Pt-solid polymer electrolyte (spe) electrodes

✍ Scribed by Akiko Aramata; Waret Veerasai

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 479 KB
• Volume: 36
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(91)85313-v

✦ Synopsis

Very rapid transient measurement of a methanol electrooxidation reaction on Pt and Pt-spe was carried out for the purpose of elucidating the reaction mechanism in acidic solution. After anodic activation treatment we observed a positive reaction current density of 1.2 mA cmm2 as a maximum value at a polarization potential (E,) of 0.6 V (us rhe) at a polarization time (7) of 38 ms in 1 M CH,OH + 0.5 M H,SO, for a true F't surface area at room temperature. In the case of the F't-spe electrode, which showed higher catalytic activity than Pt under steady-state conditions, the maximum current density of 0.8 mA cme2 at 0.6 V was observed to appear at 7 = 0.1 s, which was smaller than that on Pt itself. These results are discussed in relation to the appearance of a Poisoning effect by methanol, and to an enhancement mechanism by the spe.

The former maximum current density was corrected for by the negative reduction current of the adsorbed oxygen species and the double layer charging current, and the methanol oxidation current density was estimated as -4 mA crne2 or more at 7 < 20 ms and E, = 0.6 V. The above value of the methanol electrooxidation current density was close to the observed one of 5 mA cm-' at E of 0.6 V by using a potential sweep method of 20 V s-l.