Electrocatalytic hydrogen evolution reaction with a Cu porphyrin bearing meso-CF3 substituents

Abstract

Cu tetrakis(trifluoromethyl)porphyrin (1) was synthesized and examined as an electrocatalyst for the hydrogen evolution reaction (HER). We showed that 1 is highly efficient for the electrocatalytic HER in acetonitrile with trifluoroacetic acid (TFA) and outperforms Cu tetrakis(pentafluorophenyl)porphyrin (2) by decreasing the onset overpotential by 220 mV. The i_cat/i_p value (i_cat is the catalytic peak current and i_p is the non-catalytic peak current) with 1 is 97, while it is 53 with 2. These results suggest that for Cu porphyrins, meso-CF₃ substituents are much more effective than meso-C₆F₅ substituents to enhance the HER.