Regulating Platinum Utilization and Intrinsic Hydrogen Evolution Activity via Carbon Pore Architecture

Hydrogen evolution reaction (HER) is a key process for sustainable hydrogen production. However, its practical implementation remains limited by the high cost and inefficient utilization of platinum (Pt). Here, we investigated the influence of carbon pore architecture on Pt dispersion and intrinsic catalytic activity using a series of porous carbons spanning narrow mesoporous (MH and MH‐18; 2–5 nm), wider mesoporous (MJ010 and MJ030; 10–40 nm), and macroporous (MJ150; ~110 nm) frameworks. Pt nanoparticles formed via microwave‐assisted polyol reduction showed uniform nucleation. Macroporous MJ150 stabilizes ~2.3 nm Pt nanoparticles while preserving porosity, whereas narrow mesoporous carbons promote confinement and pore blockage, with XRD/Raman confirming higher crystallinity. XPS further shows a dominant metallic Pt ⁰ state with minimal Pt–O interactions on the macroporous support. Electrochemical measurements reveal that Pt/MJ150 exhibits superior HER performance, delivering an overpotential of 20 mV at 10 mA cm ⁻² , and higher mass activity than commercial Pt/C. C _dl , ECSA, ICP‐OES, durability, post‐HER XRD and XPS measurements confirm improved active‐site accessibility and Pt utilization, through mass transport. Overall, this study shows a clear structural–property–performance relationship, where macroporous carbon supports enable efficient Pt utilization at low loading provide a scalable strategy for HER.