Metal substitution in the metalloporphyrin linker of metal−organic framework PCN-601 for photocatalytic CO2 reduction

Metalloporphyrinic metal–organic framework PCN-601 exhibits high photocatalytic performance for CO 2 reduction. The photoreduction site was speculated to be the Ni atoms in the nodes and thus the single Ni atoms in the porphyrin centers are not effectively utilized. In this study, we applied Kohn–Sham density functional theory to investigate the effect of metal (Fe, Co, or Cu) substitution in the Ni-porphyrin linker of PCN-601 on the photocatalytic CO 2 reduction. Our results show that the photocatalytic properties of Ni-porphyrin-based PCN-601, including photoexcitation, visible-light absorption, vacuum-aligned energy level, and CO 2 adsorption strength and configuration, can be further optimized by Fe substitution in the Ni-porphyrin linker. In addition, Co-porphyrin-based PCN-601 is also found to be a promising candidate for CO 2 photoreduction though its visible-light absorption is relatively weak in comparison with its Fe- and Ni-based analogs.