Enhanced corrosion tolerance and highly durable ORR activity by low Pt electrocatalyst on unique pore structured CNF in PEM fuel cell

Abstract

Carbon supports enable Pt electrocatalyst to offer a better electrocatalytic activity and an efficient catalyst utilization in polymer electrolyte membrane fuel cells (PEMFCs). Highly graphitized carbon structure has been regarded as an active and durable catalyst support due to its high electronic conductivity and corrosion tolerant property. However, the graphitized carbon supported Pt nanoparticles may not directly correlate with a high electrochemical surface active area and electrocatalyst utilization due to the collapse of the support pore structure and Pt catalyst agglomeration. To solve this challenge, herein, we apply two different graphitization methods (thermal and catalytic graphitizations) on electrospun carbon nanofibers, which successfully control the pore structure distribution and thereby improve the utilization of Pt electrocatalyst on fibrous graphitized carbon supports. The enhanced performance of our synthesized Pt catalyst on new carbon support was investigated by the activity for oxygen reduction reaction and the corrosion tolerance using a start-up/shut-down accelerated stress test. The influence of the degree of graphitization and the proportion of the controlled meso/macroporous structures have further evaluated in a single cell system where has achieved the maximum power density of 0.85 W cm−2 due to its enhanced mass transport at high current density region. © 2020 Elsevier Ltd