Mesoporous platinum nanosponges as electrocatalysts for the oxygen reduction reaction in an acidic electrolyte

✍ Scribed by Chien-Liang Lee; Chen-Chung Wu; Hsueh-Ping Chiou; Ciou-Mei Syu; Chun-Hun Huang; Chia-Chun Yang

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 794 KB
• Volume: 36
• Category: Article
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2011.03.034

✦ Synopsis

Mesoporous Pt nanosponges of high activity were successfully synthesized for the oxygen reduction reaction (ORR). These porous nanosponges of 48.7, 53.7, 62.8, and 77 nm in size were synthesized by changing the concentration of polyvinylpyrrolidone electrolyte in the electrochemical synthesis. The electrochemically active surface areas (EASs) of the 48.7-, 53.7-, 62.8-, and 77-nm Pt nanosponges used toward H-adsorption and H-desorption were 162.84, 137.76, 116.71, and 103.83 m 2 /g, respectively. These measured EASs of these nanosponges were larger than the EAS contributed by the Pt nanoparticles of 76.69 m 2 /g. As for the ORR, electrochemical measurement and KouteckyeLevich plots showed that the kinetic current densities catalyzed by the 48.7-, 53.7-, 62.8-, and 77-nm Pt nanosponges at 0.7 V (vs. Ag/AgCl) were 0.488, 0.483, 0.450, and 0.370 mA cm À2 , respectively; and the 48.7nm Pt nanosponges had high reducing activity in the ORR. A size-dependent activity was found. As a reveal of the results of a rotating ring-disk electrode experiment, the catalysis of the ORR by the 48.7-nm Pt nanosponges occurred through the 4-electron pathway, and the efficiency of H 2 O production was approximately 99.4%.