The Design Strategy of Pt-based Electrocatalysts: Insights from Mass Transport of Fuel Cells

The mass transport is a crucial issue of proton-exchange membrane fuel cells (PEMFCs). Here, with a limiting current test and distribution of relaxation times (DRT) approach, the controllably synthesized PtCu electrocatalysts composition and size effect on mass transport of PEMFCs have been systematically investigated. The results reveal more metal doping and larger size result in a significantly negative effect on proton transport and oxygen transport in catalyst layers (CLs), respectively. Here, the proposed strategy to enhance this aspect involves using smaller-sized Pt-electrocatalysts with reduced 3d transition metal content. As a result of this strategy, the electrocatalyst demonstrated up to 16.06% and 62.13% higher efficiency at 1.3 A cm-2 compared to its larger and richer Cu-doped counterparts, respectively. These results will inspire future Pt-based electrocatalyst development, aiming to achieve higher power densities, enhanced efficiencies, and cost-effective PEMFCs.