Semi-ordered catalyst layer with ultra-low Pt loading for proton exchange membrane fuel cells

The reduction of platinum group metal (PGM) loading for proton exchange membrane fuel cells (PEMFC) is essential for their widespread deployment. The structural ordering of the catalyst layer is considered as an important means to enhance the power generation performance and hence reduce the PGM loading. In this study, we present a semi-ordered catalyst layer structure design that significantly diminishes mass transport resistance while enhancing H⁺ transport. The ordered micro-array (OMA) with intrinsic internal voids, establishes the vertical channels within the catalyst layer and optimizes the transport pathways for protons and oxygen. Thus, the semi-ordered catalyst layer design exhibits significantly improved MEA performance by 24 % and lower oxygen transport resistance at low loading (0.05–0.1 mg_Pt cm⁻²) compared to conventional planar catalyst layer. The multiphysics modelling demonstrates the role of vertical pore channels in the semi-ordered catalyst layer for mass transport in the catalyst layer, which can further reduce the Pt loading while maintaining high fuel cell performance.