Synthesis of an imine-type nickel complex and investigation of its electrocatalytic activity for H2 evolution

Abstract

We report on the synthesis and characterization of an imine-type nickel complex produced via the complexation of an in situ generated 2-(iminomethyl)phenol ligand with Ni^II ion. The use of this complex as an electrocatalyst for H₂ evolution in a DMF solution, with acetic acid as the proton source, was investigated in detail, employing both experimental analyses (electrochemical analysis, spectroscopy analysis) and theoretical analysis (plateau current analysis). The overpotential required for H₂ evolution is about 590 mV with a faradaic efficiency of 49% after 3 hours bulk electrolysis, competing with the two-electron reduction of free-imine groups in the ligand. The maximal TOF was estimated to be about 12 860 s⁻¹ on the basis of a CECE mechanism.