The steric hindrance effect of Co porphyrins promoting two-electron oxygen reduction reaction selectivity

Abstract

A new Co 5,10,15,20-tetrakis(2',6'-dipivaloyloxyphenyl) porphyrin (1) with eight ester groups in all ortho and ortho′ positions of phenyl groups was designed, which displayed significantly improved 2e oxygen reduction reaction (ORR) selectivity compared with 5,10,15,20-tetrakis(para-dipivaloyloxyphenyl) porphyrin (2) without large steric groups. This work is significant to reveal the steric hindrance effect of metal porphyrins on electrocatalytic ORR selectivity.