Controllable construction of Pt/CNT catalyst layers to improve Pt utilization in PEMFCs

Abstract

Reducing Pt-group metal (PGM) usage while maintaining high power output and durability is significant for the large-scale commercialization of proton exchange membrane fuel cells (PEMFCs). Herein, membrane electrode assemblies (MEAs) with ultra-low Pt loading are controllably constructed using carbon nanotube-supported platinum (Pt/CNT) catalysts with high catalytic efficiency. The fuel cell and accelerated stress tests (ASTs) show that the MEA with the Pt/CNT cathode catalyst layer (CCL, 0.1 mg_Pt cm⁻²) exhibits superior performance and durability compared to that prepared with conventional commercial Pt/C. For the Pt/CNT MEA (both the anode and cathode utilize Pt/CNT), the normalized peak power density reaches 20.3 W mg_Pt⁻¹, which is 1.77 times higher than that of Pt/C MEA (11.5 W mg_Pt⁻¹). The excellent performance of the Pt/CNT CL is attributed to effective mass transfer, the high degree of graphitization of CNTs and the Pt utilization rate. The obtained results can guide the widespread use of CNTs in fuel cell catalyst synthesis.