Carbon core-shell Pt nanoparticle embedded porphyrin Co-MOF derived N-doped porous carbon for the alkaline AEM water electrolyzer application

Industrial clean hydrogen (H₂) production using efficient and durable electrocatalysts is an essential goal for developing future renewable energy systems. Herein, we report the synthesis of carbon core-shell platinum (Pt) nanoparticles embedded in porphyrin cobalt (Co) metal-organic framework (MOF) derived nitrogen-doped porous carbon (Pt@Co-NPC) via pyrolysis of Pt-aniline complex/Co-MOF at 600-800 °C for the H₂ evolution reaction (HER). In 1.0 M KOH electrolyte medium, the resulting Pt@Co-NPC-800 electrocatalyst achieved a low overpotential of 34 mV to reach 10 mA cm⁻², together with a Tafel slope of 42.72 mV dec⁻¹, and good stability for more than 96 h at a current density of 100 and 200 mA cm⁻² compared to commercial Pt nanoparticles with a carbon support (Pt/C). Notably, high surface area (263.40 m² g⁻¹) porous carbon materials with uniformly distributed Pt@Co nanostructures provided better HER electrocatalytic activity. Moreover, density functional theory (DFT) calculations reveal that the improved HER activity of the Pt@Co-NPC-800 electrocatalyst arises from the enhanced synergetic effect between the Pt and Co, which induces the favourable Gibbs free-energy value of −0.120 eV for H* adsorption in the Pt active site. Besides, the fabricated anion exchange membrane water electrolyzer (AEMWE) achieved a current density of ∼1.32 A cm⁻² at 2.34 V_cell in 1.0 M KOH, 60 °C. The designed Pt@Co-NPC-800 electrocatalyst provides a new direction to make efficient AEMWEs.