Nitrogen and sulfur co-doped mesoporous carbon as cathode catalyst for H2/O2 alkaline membrane fuel cell – effect of catalyst/bonding layer loading

• Using N-S-MPC as cathode catalyst, the effects of catalyst/bonding layer on the power generation are investigated.
• The power density increased with increasing N-S-MPC loading, and reached the maximum when loading is 3 mg cm−2.
• The local hydroxyl ion concentration is important, which was favorably for the process of ORR.
• The bonding layer has a great influence on the MEA performances.
• The MEA using 30 μL bonding layer produced a maximum power density of AMFC.

In this study, nitrogen and sulfur co-doped mesoporous carbon (N-S-MPC) materials are selected as the platform to demonstrate the potential of N-S-MPC to replace precious metal catalyst for fuel cell cathode oxygen reduction. Using both N-S-MPC and commercial available 40%Pt/C as cathode catalysts, the effects of catalyst and bonding layer in the catalyst layer (CL) on the power generation performances are thoroughly investigated for alkaline membrane fuel cells (AMFCs). Through single cell tests, several observations are reached as follows: (1) For N-S-MPC cathode, with increasing N-S-MPC loading from 1.00 to 5.00 mg cm−2, the power density reached the maximum (21.7 mW cm−2) when the catalyst loading is 3 mg cm−2. However, for Pt/C cathode the power density reached the maximum (21.3 mW cm−2) for a catalyst loading of 0.5 mg cm−2, with increasing loading from 0.3 to 0.5 mg cm−2; (2) Increasing the thickness of catalyst layer resulted in an increase in power density. Thus, raising the local hydroxyl ion concentration was in favor of the process of oxygen reduction reaction. (3) The bonding layer also has a significant influence on the MEA fabrications, where the MEA using 30 μL bonding layer produced a maximum power density of 20.8 mW cm−2.