Interface between anode porous transport layer and catalyst layer: A key to efficient, stable and competitive proton exchange membrane water electrolysis

This review examines advancements in the design of the anode porous transport layer (PTL) and catalyst layer (CL) interface in proton-exchange membrane water electrolysis (PEMWE). The quality of PTL-CL interface (contact area and contact resistance per area) is critical to electrolyser performance, influencing the voltage losses (polarisation and ohmic) and stability. To mitigate issues associated with Ti PTL passivation and enhance charge transport, various noble metal coatings, have been explored. Ir coatings seems to be the optimal solution due to their stability and catalytic activity. The review highlights surface modification techniques such as physical vapour deposition, electroplating, and laser ablation, as well as the development of porous transport electrodes and microporous layers. These approaches aim to optimise the performance of the electrolyser while minimising the noble metal usage. The findings underscore the importance of material choice and surface nano/microscale morphology of the interface in achieving cost-effective and durable PEMWE systems. • Coating anode PTL with Pt or Ir is crucial to ensure long-term stability. • Ir coating can fulfil the function of the catalyst. • Combination of Pt or Ir coating and low-loading catalyst layer enhances performance. • Nano-structuring of the PTL surface has positive impact on the performance. • Time stability of low Ir content systems needs more attention.