• A novel triple-layer Ti-porous transport layer (PTL), fabricated using a practical and scalable tape casting and roll calendering process, enhances catalyst utilization by increasing interfacial contact area and the triple-phase boundary.
• The ultra-high porosity (75%) backing layer and graded structure maximize oxygen transport, mitigate oxygen accumulation, and improve reactant accessibility.
• Electrochemical evaluations demonstrate a 127 mV reduction in voltage at 2 A cm−2 compared to a commercial PTL, accelerating proton exchange membrane water electrolysis commercialization and supporting the transition to sustainable energy.
• Digital twin technology using X-ray revealed increased contact area and triple-phase boundary at the interface with the catalyst layer, significantly improving oxygen evolution reaction kinetics.