Free-standing and ionomer-free 3D platinum nanotrough fiber network electrode for proton exchange membrane fuel cells

Herein, a nanotrough-like catalyst layer (NTCL) with low Pt loading and enhanced durability was developed directly as the cathode for proton-exchange membrane fuel cells (PEMFCs). Benefiting from the biomimetic architecture and ultrathin thickness, the mass transport of reactants and water management in the cathode are significantly enhanced. A peak power density of 0.936 W cm⁻² is achieved with a Pt loading of 42 μg cm⁻² in the cathode. Besides, the in-situ observation of water formation on the NTCL by the environmental scanning electron microscopy (ESEM) verified the efficient water management. Importantly, the Pt NTCL cathode is far more stable than the conventional electrode during the accelerated stress tests. The enhanced durability may be attributed to a self-healing mechanism, which involves Pt dissolution and re-deposition, endowing the NTCL with outstanding robustness. This work highlights a new approach to preparing and understanding nanostructured Pt electrodes with enhanced performance and durability for PEMFCs.