The influence of UPD-lead on the adsorption of formaldehyde, formic acid and methanol on Pt in acid solution

✍ Scribed by M. Bełtowska-Brzezinska; J. Heitbaum; W. Vielstich

• Publisher: Elsevier Science
• Year: 1985
• Tongue: English
• Weight: 597 KB
• Volume: 30
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(85)80007-4

✦ Synopsis

Using fast linear sweep voltammetry, the adsorption behaviour of formaldehyde, formic acid and methanol was studied on an electrochemically modified (100~like Pt electrode without or covered with UPD-lead. It was found that both the lead inhibits the formation of strongly bound intermediates and the intermediates inhibit the deposition of lead. This is explained by a mutual hindrance after the "third body" concept. This cannot explain, however, the electrccatalytic effect of UPD-lead on the oxidation of the above fuels since this effect has its maximum at a,, > 0.5. Therefore, we postulate that UPD-lead catalyzes the direct oxidation of formic acid and formaldehyde at potentials between 0.2 and 0.7 V. On the other hand, the dirat oxidation of methanol on smooth Pt occurs at potentials more positive than 0.6 V where UPD-lead is already anodically dissolved. Therefore, only a small catalytic effect of UPD-lead on methanol oxidation is observed.