Pt-based electrocatalysts for polymer electrolyte membrane fuel cells prepared by supercritical deposition technique

• Published in: Journal of power sources Vol. 179; no. 2; pp. 532 - 540
• Main Authors: BAYRAKCEKEN, Ayse, SMIRNOVA, Alevtina, KITKAMTHORN, Usanee, AINDOW, Mark, TÜRKER, Lemi, EROGLU, Inci, ERKEY, Can
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier Sequoia 01.05.2008
• Subjects: Applied sciences; Catalysis; Catalysts; Deposition; Electrocatalysts; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Platinum; Reduction; Surface area; Voltammetry; Particle size; Electrocatalyst; Polymer electrolytes; Carbon dioxide; Carbon nanotubes; Carbon; Cyclic voltammetry; Electrocatalysis; Polymer electrolyte membrane fuel cell; Supercritical carbon dioxide deposition; Transmission electron microscopy; Platinum; X ray diffractometry; Catalyst; Fuel cell
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2007.12.086

Pt-based electrocatalysts were prepared on different carbon supports which are multiwall carbon nanotubes (MWCNTs), Vulcan XC 72R (VXR) and black pearl 2000 (BP2000) using a supercritical carbon dioxide (scCO sub(2) deposition technique. These catalysts were characterized by using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and cyclic voltammetry (CV). XRD and HRTEM results demonstrated that the scCO) sub(2) deposition technique enables a high surface area metal phase to be deposited, with the size of the Pt particles ranging from 1 to 2 nm. The electrochemical surface areas (ESAs) of the prepared electrocatalysts were compared to the surface areas of commercial ETEK Pt/C (10 wt% Pt) and Tanaka Pt/C (46.5 wt% Pt) catalysts. The CV data indicate that the ESAs of the prepared Pt/VXR and Pt/MWCNT catalysts are about three times larger than that of the commercial ETEK catalyst for similar (10 wt% Pt) loadings. Oxygen reduction activity was investigated by hydrodynamic voltammetry. From the slope of Koutecky-Levich plots, the average number of electrons transferred in the oxygen reduction reaction (ORR) was 3.5, 3.6 and 3.7 for Pt/BP2000, Pt/VXR and Pt/MWCNT, correspondingly, which indicated almost complete reduction of oxygen to water.