Impact of the Ionomer/Carbon Ratio and Pt Loading on the Three-Phase Boundary in a Cathodic Catalytic Layer via Coarse-Grained Molecular Dynamics Simulation

SK Jiang and JL Pan and MM Deng and MT Li and N Yang and L Li and ZD Wei, JOURNAL OF PHYSICAL CHEMISTRY C, 127, 21963-21970 (2023).

DOI: 10.1021/acs.jpcc.3c04754

Optimization of the cathodic catalytic layer (CCL) is important for enhancing the performance of proton exchange membrane fuel cells and reducing platinum (Pt) usage. Herein, we investigate the mesostructure of the CCL with varying ionomer/carbon (I/C) ratios and Pt/carbon (Pt/C) loading via coarse-grained molecular dynamics simulation. The distribution of Pt/C catalysts and Nafion ionomers shows that the I/C ratio affects the formation of electron, proton, and gas/liquid transport channels and the three-phase boundary differently with low and high Pt loading. The statistical proportion of Pt particles at the three-phase boundary reveals that Pt utilization depends only on proton transport channels with a low Pt loading. However, it relies on the relation between proton and gas/liquid transport channels with medium and high Pt loading. We identified the well-matched I/C ratio and Pt loading via screening for optimal Pt utilization. Thus, the three-phase boundary was optimized for reducing the use of Pt in the CCL.

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