Boosting PEM fuel cell performance with a designed mesoporous carbon-supported catalytic layer

Abstract

The mesoporous carbon-supported (MCS) catalytic layer (CL) has a great specific surface area, thereby benefiting the formation of Pt active sites within the CLs of polymer electrolyte membrane (PEM) fuel cells. The primary pores of mesoporous carbons (MCs) significantly impact electrochemical reactions and mass transport inside the MCS CL, consequently affecting fuel cell performance. A stochastic algorithm is employed to recreate the microstructure of the MCS CL. The effects of primary pore size, depth and number on oxygen reduction reaction (ORR) within the MCS CL, considering the Pt poisoning effects resulting from the intruded ionomer, are evaluated via the lattice Boltzmann (LB) method. The simulation findings show that a larger primary pore size promotes mass transfer inside the MCS CL; nevertheless, the ionomer tends to invade the pores, causing Pt poisoning, especially under a high ionomer intrusion ratios. Furthermore, increasing the pore depth and number initially increases and consequently decreases the ORR rate. The result indicates that the optimal primary pore size, depth, and number for MCS CL are 6 nm, 15 nm, and 6, respectively. Ultimately, the ORR rate is increased from 2.51e-15 mol s⁻¹ for the conventional SC CL to 6.73e-15 mol s⁻¹ for the optimal MCS CL.