Electrochemical impedance studies of electrooxidation of methanol and formic acid on Pt/C catalyst in acid medium

✍ Scribed by Zhen-Bo Wang; Yuan-Yuan Chu; Ai-Fen Shao; Peng-Jian Zuo; Ge-Ping Yin

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 736 KB
• Volume: 190
• Category: Article
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2009.01.008

✦ Synopsis

Cyclic voltammetry (CV), amperometric it experiments, and electrochemical impedance spectroscopy (EIS) measurements were carried out by using glassy carbon disk electrode covered with the Pt/C catalyst powder in solutions of 0.5 mol L -1 H 2 SO 4 containing 0.5 mol L -1 CH 3 OH and 0.5 mol L -1 H 2 SO 4 containing 0.5 mol L -1 HCOOH at 25 • C, respectively. Electrochemical measurements show that the activity of Pt/C for formic acid electrooxidation is prominently higher than for methanol electrooxidation. EIS information also discloses that the electrooxidation of methanol and formic acid on the Pt/C catalyst at various polarization potentials show different impedance behaviors. The mechanisms and the rate-determining steps of formic acid electrooxidation are also changed with the increase of the potential. Simultaneously, the effects of the electrode potentials on the impedance patterns were revealed.