Suppression of Schottky Effect with Highly Corrosion-Resistant Coating on Porous Transport Layers for Interface Optimization in Proton Exchange Membrane Electrolyzers
Proton exchange membrane water electrolyzers (PEMWEs) are pivotal for sustainable hydrogen production, yet the corrosion-induced TiOx on porous transport layers (PTLs) introduces Schottky contact barriers and pinch-off effects, severely impeding charge transfer and efficiency. Here, a cost-effective MoIrOx coating via spray deposition and thermal treatment on Ti felts is proposed. The coating forms a conductive interlayer that establishes a Schottky barrier staircase, reducing the effective electron transfer barrier and isolating TiOx from the ionomer to mitigate the pinch-off effect. The optimal PTL achieves a current density of 3.27 A cm−2 at 2 V, surpassing uncoated Ti felts by 59.5%. The MoIrOx interlayer suppresses localized electron accumulation at the interface, enabling stable operation with ultra-low catalyst loadings by preventing direct ionomer-TiOx contact. This work demonstrates a scalable strategy to enhance PEMWE efficiency and durability while minimizing precious metal reliance, offering critical insights into interface engineering for electrolyzers.