Modulating Pt nanoclusters/carbon support interaction for highly efficient and tolerant hydrogen evolution in PEM water electrolysis with ultra-low Pt loading

Pt-based catalysts are known for their efficiency in the hydrogen evolution reaction (HER) in proton exchange membrane water electrolyzers (PEMWE). However, reducing Pt loading while maintaining high HER activity remains challenging. We propose a strategy to enhance the catalytic activity of Pt through surface modifications with heteroatom-doped carbon black support, strengthening Pt-carbon interactions and enabling uniform immobilization of Pt nanoclusters. Pt catalysts on N, O-co-doped carbon black (Pt/NOCB) exhibited superior HER activity compared to those on surface-oxidized carbon black (Pt/OCB) and pristine carbon black (Pt/CB). Pt/ NOCB demonstrated a low overpotential of 18 mV at 10 mA/cm2, versus 36 mV for Pt/CB. Additionally, Pt/ NOCB showed a 27-fold increase in turnover frequency and a 7.38-fold enhancement in mass activity at an overpotential of 50 mV, compared to commercial 20 wt% Pt/C. Characterizations and density functional theory (DFT) calculations indicate that robust metal-support interactions at the Pt-C interface optimize hydrogen adsorption free energy (Delta GH*) and enhance atomic utilization. Pt/NOCB also performed excellently as cathode catalysts with ultra-low Pt loading in practical PEMWE. At a typical low Pt loading of 0.05 mg/cm2, Pt/NOCB0.05 achieved low voltages of 1.5936 V at 1 A/cm2 and 1.7498 V at 3 A/cm2, outperforming 20 wt% Pt/C-0.05. The electrolyzer based on Pt/NOCB-0.05 showed remarkable stability approximately 3300 h at a degradation rate of 20.20 mu V/h. This strategy presents a promising avenue for developing cost-effective, highly active, and durable electrocatalysts for PEMWE.