High-performance ionomer-free gas diffusion cathodes with low Pt loading for proton exchange membrane water electrolysis

Platinum (Pt) is recognized as the most active material for the hydrogen evolution reaction in acidic media; however, its catalytic activity is often underestimated in proton exchange membrane water electrolysis (PEMWE) due to poor utilization of the cathode catalyst layer. In this study, we present the synthesis, characterization, and application of Pt nanoparticles with atomic precision on a microporous-layer-coated gas diffusion layer for PEMWE. The Pt nanoparticles were synthesized via atomic layer deposition, a technique that enables precise control over loading and particle size at the atomic scale. The resulting gas diffusion electrode with an exceptionally low platinum loading (1.08-5.40 μg cm^- ²) demonstrated mass activity at least one order of magnitude higher than that of benchmark Pt. Furthermore, the electrode exhibited exceptional stability at a current density of 1 A cm^- ² over 200 hours. It also showed robust performance under dynamic operation, enduring 25,000 cycles of alternating cell voltages between 1.45 V and 2 V.