Trifluoromethyl‐Modified A ₂ B‐Type Cobalt Triaryl Corroles as Electrocatalysts for Hydrogen Evolution

ABSTRACT To address the urgent demand for energy transition, developing efficient and sustainable hydrogen energy technologies is of great significance. This study focuses on the electrocatalytic hydrogen evolution reaction (HER) using molecular catalysts. Three new cobalt corrole complexes—5,15‐bis(pentafluorophenyl)‐10‐(trifluoromethylphenyl)cobalt corroles ( 1 , 2 , 3 ) bearing o‐ , m‐ , and p ‐trifluoromethyl substituents at the meso ‐10‐phenyl position were synthesized as electrocatalysts for HER. The regioisomeric placement of the ─CF 3 group ( o ‐, m ‐, p ‐) was designed to probe its position impact on catalytic HER efficiency. It turned out that all complexes exhibited significant activity for catalyzing HER in both organic and buffered aqueous solutions. The activity follows an order of 1 > 3 > 2 , indicating the position of ─CF 3 group on 10‐phenyl exerts an obvious influence on their catalytic efficiency. When using trifluoroacetic acid or p ‐toluenesulfonic acid as the proton source in the organic phase, the catalytic HER goes via an EECC (electron–electron–proton–proton) pathway. Under conditions of 938 mV overpotential in a near‐neutral aqueous system, complex 1 reached a hydrogen evolution turnover frequency (TOF) of 170.67 h −1 .