Embedded Platinum Clusters with Modulated Electronic Metal-Support Interaction for Superior Hydrogen Evolution

Although nanoscale platinum catalysts have attracted considerable attention for the hydrogen evolution reaction, achieving precise control over size, dispersion, and electronic metal-support interaction remains a critical challenge. In this work, we present a wall-embedding confinement strategy to achieve regulation of the size of Pt (Pt clusters and Pt nanoparticles) within the self-catalytically grown flexible nitrogen-doped carbon framework (Ni-CNTs/NCF). The spatial geometric confinement effect arising from the porous carbon support's wall-embedding structure and the interaction between metal Ni and Pt species effectively prevent aggregation of Pt species, and the changes caused by the size difference of Pt species optimize H* adsorption energy. The results show that the strong interaction between the Pt clusters and the support enables the adsorption free energy of hydrogen to nearly ideal values, achieving overpotentials of 213 mV (1.0 M KOH) and 130 mV (0.5 M H₂SO₄) at 100 mA cm^-2, significantly lower than those of Pt nanoparticles (267/205 mV) and commercial Pt/C (287/158 mV). Notably, the Pt clusters demonstrate 7-fold enhancements in mass activity and turnover frequency compared to Pt/C despite using substantially reduced Pt loading. When integrated into proton exchange membrane electrolyzers, the Pt clusters cathode demonstrates superior performance to commercial Pt/C systems, maintaining stability over 200 h of continuous operation.