Electrocatalytic Hydrogen Evolution of Cobalt and Free‐base Triaryl Corrole Bearing Hydroxyethyl Amino Groups

Abstract

Four free‐base corroles (F15C, F12C, F10C, F8C) and their cobalt(III) complexes were used as homogeneous electrocatalysts for hydrogen evolution using acetic acid, trifluoroacetic acid and water as proton sources. Free‐base corrole was firstly reported as electrocatalyst for H2 evolution. The results showed that free‐base corrole was active in electrocatalytic hydrogen evolution reaction (HER) in trifluoroacetic acid. And cobalt(III) corroles bearing hydroxyethyl amino groups were more efficient in HER as compared to their benchmark corroles. The catalytic active species of four tested cobalt(III) corroles were CoII‐H in acetic acid/dimethylformamide solvent. In water solution, both CoIII‐H and CoII‐H may be involved in HER. Interestingly, when trifluoroacetic acid was used as proton source, CoII‐H was the mainly active intermediate for F15CCo and F10CCo, and CoIII‐H for F12CCo and F8CCo, respectively. As for the free‐base corrole, (·Cor)H4 and [(·Cor)H3]– were the catalytic active species.