Constructing low PGM loading on porous transport layer (PTL) for PEMWE application: simulated ex-situ analysis in 3D printed flow cell

The prolonged acidic environment of proton exchange membrane water electrolyzers (PEMWE) promotes the formation of TiO x on Ti-based porous transport layers (PTLs), eventually increasing the overpotential. PGM-based coatings are therefore essential to suppress TiO x formation and maintain low overpotential. However, high PGM loadings on Ti PTLs increase the capital expenditure. This work combines sputtering with post-deposition thermal treatment to develop a Ti PTL with enhanced durability under the tested conditions at a low PGM loading of 0.085 mg cm −2 . In ex-situ corrosion analysis, the thermally treated (2 h at 400 0 C), IP-0.08-400 Ti PTL exhibited a higher corrosion potential (−0.22 V) than its as-coated counterpart. Whereas, in 150 h of in-situ testing, the IP-0.08-400 Ti PTL exhibited lower cell voltage by 30 mV with a 2.5-times lower degradation rate (24 μV h −1 ) compared to as-coated IP-0.08. Also, during a simulated ex-situ end-of-life test under PEMWE conditions, IP-0.08-400 Ti PTL exhibited ∼3.25 times greater lifetime, which outperformed the as-coated IP-0.08.