Recent Progress in Heteroatom-Containing Metalloporphyrin-Based Catalysts for CO₂ Reduction

Metalloporphyrins, owing to their structural resemblance to natural enzyme active sites and highly tunable coordination environments, have emerged as promising catalysts for converting CO₂ into value-added chemicals and fuels. Considerable efforts have been made to modify metalloporphyrins to improve their catalytic capability for CO₂ reduction. One approach involves modifying the metal coordination environment (known as the first coordination sphere) to generate heteroatom-containing metalloporphyrins, particularly N-confused and O/S-substituted variants. While heteroatom-containing metalloporphyrins were first synthesized in 1989, their use in CO₂ reduction catalysis was not reported until after 2020. Herein, we review the recent progress in the design, catalytic performance, and mechanistic studies of N-confused and O/S-substituted metalloporphyrins towards CO₂ reduction. This review encompasses both experimental and theoretical computational work, as well as the use of porphyrins as catalysts in photocatalysis and electrocatalysis. Finally, based on the current research advances, we present critical recommendations and future research directions, with a focus on theoretical studies, in the hope of facilitating the rational design of novel catalysts for sustainable energy conversion and environmental remediation.