A framework ensemble facilitates high Pt utilization in a low Pt loading fuel cell

Proton-exchange membrane fuel cells (PEMFCs) are a clean, zero-emission, and promising energy technology for future use. The scale-up of PEMFCs drives up the cost of Pt resources, a key catalytic material for fuel cells; this inevitably necessitates the development of low-Pt-usage and high-Pt-utilization technology for PEMFCs. Herein, we report a low-Pt-loading membrane electrode assembly (MEA) featuring a three-dimensional (3D) carbon framework with embedded PtZn intermetallic nanoparticles (iNPs) and vacuum-aspirated Nafion ionomers. Such a framework ensemble shows efficient mass transfer for various species (protons, O 2 , and water) to the PtZn iNPs. As a result, the maximum power output reaches 826 mW cm −2 at a loading of 60 μg Pt cm −2 for a PEMFC fabricated with the as-prepared MEA, and a high Pt utilization of 145 mg Pt kW −1 is realized, which is 1.6 times greater than that of a commercial Pt/C catalyst. Moreover, excellent stability is achieved at low Pt loading (60 μg Pt cm −2 ), with no decay occurring during 300 h of continuous operation. Rationally designing the structure of catalyst layer in MEA to achieve the dispersion of active sites at the cross of three-phase field and the effective transfer network paths for protons through catalysts and catalyst layer.