Enhanced long-term durability of proton exchange membrane fuel cell cathode by employing Pt/TiO 2/C catalysts

Abstract

Pt/TiO 2/C catalysts are employed as the cathode catalysts for proton exchange membrane fuel cell (PEMFC). The comparative studies on the Pt/C and Pt/TiO 2/C catalysts are conducted with the physical and electrochemical techniques. After the accelerating aging test (AAT), the remaining electrochemical active surface area (EAS) of the Pt/TiO 2/C catalysts is 75.6%, which is larger than that of the Pt/C catalysts (42.6%). The apparent exchange current density ( i app 0 ) of the oxygen reduction reaction (ORR) at the Pt/C catalysts decreases from 3.02 × 10 −9 to 1.32 × 10 −11 A cm −2 after the AAT. And the value of i app 0 of the ORR at the Pt/TiO 2/C catalysts is 2.88 × 10 −9 A cm −2 before the AAT and 2.51 × 10 −9 A cm −2 after the AAT. Furthermore, the output performance degradation of the PEMFC using the Pt/TiO 2/C cathode catalysts is also less than that using the Pt/C catalysts. The particle size of the Pt/C catalysts increases significantly from 5.3 to 26.5 nm after the AAT. The mean particle size of the Pt/TiO 2/C catalysts is 7.3 nm before the AAT and 9.2 nm after the AAT. It can be concluded that the long-term durability of the Pt/TiO 2/C catalysts in a PEMFC is much better than that of the Pt/C catalysts.