Electrocatalytic hydrogen evolution using triaryl corrole cobalt complex

Three cobalt triaryl corroles bearing an electron‐withdrawing or electron‐donating group at 10‐meso‐phenyl were synthesized and characterized. Two of them are new cobalt corroles prepared in this study. These cobalt corroles were characterized using high‐resolution mass spectrometry, UV–Vis., nuclear magnetic resonance, X‐ray photoelectron spectroscopy, and single‐crystal X‐ray structure determination. All synthesized cobalt corroles efficiently catalyzed the hydrogen evolution reaction (HER) in neutral aqueous media at an overpotential of 838 mV. The HER activity of these cobalt corroles significantly depended on the virtue of peripheral substituents. Three A2B‐type cobalt triaryl corroles having different electron structures were used as electrocatalysts for hydrogen evolution in nonaqueous and aqueous media.