Efficient Water Dissociation on Confined Ultrafine Pt via Pyridinic N-Enhanced Heavy d-p Interaction

Sluggish water dissociation on Pt electrocatalysts results in poor performance for the alkaline hydrogen evolution reaction (HER) and thus greatly limits their practical application in industrial water electrolysis. Herein, ultrafine Pt nanoparticles have been confined into N-doped carbon by an in situ galvanic replacement reaction, and the pyridinic N-enhanced heavy d-pi interaction is found to significantly enhance the water dissociation catalytic activity of Pt. The electron-deficient Pt generated by this enhanced heavy d-pi effect exhibits an ultralow overpotential for hydrogen evolution of 10 mV at a current density of 10 mA cm(-2) and an ultrahigh mass current density of 7.74 mA mu g(Pt)(-1) at an overpotential of 70 mV (7.9-fold higher than that of commercial Pt/C). Theoretical calculations reveal that the pyridinic N-enhanced heavy d-pi effect can largely reduce the water dissociation energy barrier on Pt, thus greatly enhancing Pt's performance for the alkaline HER.