Abstract:
This work was carried out to study the effects of supports on activity and stability of Pt-based electrocatalyst for oxygen reduction reaction (ORR) in PEM fuel cell. The work was separated into 2 parts. The first part was the comparative studied of activity and stability of Pt-M/C (M = Pd and Co) relative to that of Pt/C prepared by a combined approach of impregnation and seeding for ORR in low temperature fuel cells. According to the activity test in a single PEM fuel cell, Pt-Pd/C exhibited the maximum current density of 469 mA/cm² at 0.6 V and 9.95 mA/cm² at 0.9 V. With regard to the stability test in acid solution (0.5 M H₂SO₄), the Pt-Pd/C exhibited the most stability compared with other electrocatalysts. The second part was the preparation of Pt-Pd electrocatalyst on 4 types of support including Vulcan XC72 (C), Hicon black (HB), carbon nanotube (CNT) and titanium dioxide (TiO₂) via a combined approach of impregnation and seeding. From the activity test in a single PEM fuel cell, Pt-Pd/C Pt-Pd/HB Pt-Pd/CNT and Pt-Pd/TiO₂ exhibited the current density of 469, 474, 443 and 231 mA/cm² at 0.6 V, respectively. Likewise to the stability test in acid solution, Pt-Pd/CNT showed the most stability compared with others after 1000 cycles. Moreover, the ORR on all supported Pt-Pd electrocatalysts followed the 4-electron pathway.