Structural engineering and electronic modulation of ZIF-67 derived Ptx-CoSe2@NC hierarchical catalysts for efficient alkaline hydrogen evolution

The development of low-platinum electrocatalysts with high activity in alkaline media is critical for sustainable and cost-effective hydrogen production. In this study, we report a dual-phase engineering strategy to synthesize Pt-CoSe₂ nanoparticles embedded in nitrogen-doped carbon (Pt-CoSe₂@NC) via controlled pyrolysis of ZIF-67. The resulting catalyst features hierarchical porosity and a 3D conductive network that confines ultrafine Pt particles and enhances interfacial charge and mass transfer. Strong Pt-CoSe₂ interactions induce electron redistribution, elevating cobalt oxidation states and optimizing hydrogen adsorption energetics. Nitrogen doping and surface-oxygenated Co species further boost performance. The optimized Pt-CoSe₂@NC catalyst exhibits an overpotential of 37.4 mV at 10 mA cm⁻², a Tafel slope of 60.4 mV dec^-1, and remains over 90 % of its initial current density after 24 h in 1 M KOH. Density functional theory (DFT) calculations reveal a shift in the d-band center of Pt due to Pt-CoSe₂ interface formation, leading to near-thermoneutral hydrogen adsorption energy. This work integrates MOF-derived structural control with electronic interface modulation, offering a generalizable blueprint for designing efficient, low-noble-metal HER catalysts.