J. Phys. Chem. C 2009, 113, 15707–15713
15707
Pt Degradation Mechanism in Concentrated Sulfuric Acid Studied Using Rotating Ring-Disk Electrode and Electrochemical Quartz Crystal Microbalance Minoru Umeda,*,† Yu Kuwahara, Akira Nakazawa, and Mitsuhiro Inoue Department of Materials Science and Technology, Faculty of Engineering, Nagaoka UniVersity of Technology, Kamitomioka 1603-1, Nagaoka, Niigata 940-2188, Japan ReceiVed: April 29, 2009; ReVised Manuscript ReceiVed: July 14, 2009
In this paper, we describe our electrochemical investigation of platinum degradation in concentrated sulfuric acid. The Pt electrode weight is found to decrease by an alternating potential cycle between +0.5 V vs Ag/Ag2SO4. No marked weight decrease occurs by excluding the former or latter region. Also, electrochemical reactions that participate in Pt dissolution and occur between the two potential regions were studied by a rotating ring-disk electrode (RRDE) method. The obtained voltammogram indicates (i) the electrodeposition of sulfur at
