A super-efficient cobalt catalyst for electrochemical hydrogen production from neutral water with 80 mV overpotential

Abstract

Self-assembled molecular iron and cobalt catalysts (MP₄N₂, M = Fe, Co) bearing a multihydroxy-functionalized tetraphosphine ligand electrocatalyze H₂ generation from neutral water on a mercury electrode at −1.03 and −0.50 V vs. NHE, respectively. Complex CoP₄N₂ displays extremely low overpotential (E_onset = 80 mV) while maintaining high activity and good stability. Bulk electrolysis of CoP₄N₂ in a neutral phosphate buffer solution at −1.0 V vs. NHE produced 9.24 × 10⁴ mol H₂ per mol cat. over 20 h, with a Faradaic efficiency close to 100% and without apparent deactivation.