PtIr/CNT as anode catalyst with high reversal tolerance in PEMFC

Abstract

Cell reversal has a significant impact on the durability of proton exchange membrane fuel cell (PEMFC). Oxygen evolution reaction (OER) catalysts are often introduced to serve as reversal tolerant materials. However, adding OER catalysts to the anode may lead to a reduction in performance as they could potentially cover the active Pt site. In this study, carbon nanotube (CNT) supported Pt-Ir bifunctional catalyst is used as the anode catalyst to balance the tradeoff between cell reversal resistance and power generation performance. The obtained Pt3Ir1/CNT catalyst exhibits a faster OER kinetic (83.8 mV dec−1) than the commercial Pt/C (151.8 mV dec−1) catalyst and the similar hydrogen oxidation reaction (HOR) activity with Pt/C. After the accelerated durability test, the electrochemical active surface area (ECSA) loss of Pt3Ir1/CNT is 19.6% while that of Pt/C is 54.7%. After 50 consecutive cell reversal tests, it was observed that the MEA with Pt3Ir1/CNT exhibits almost no degradation in cell voltage. In contrast, the MEA with Pt/C showed a degradation of 4.9% (@ 1000 mA cm−2) when subjected to the same conditions. The strategy of combing bifunctional catalysts with high-durability supports has been shown to improve the reversal tolerance of the cell without performance loss.