Energy Band Alignment and Redox‐Active Sites in Metalloporphyrin‐Spaced Metal‐Catechol Frameworks for Enhanced CO2 Photoreduction

Abstract Two new chemically stable metalloporphyrin‐bridged metal‐catechol frameworks, InTCP‐Co and FeTCP‐Co, were constructed to achieve artificial photosynthesis without additional sacrificial agents and photosensitizers. The CO 2 photoreduction rate over FeTCP‐Co considerably exceeds that obtained over InTCP‐Co, and the incorporation of uncoordinated hydroxyl groups, associated with catechol, into the network further promotes the photocatalytic activity. The iron‐oxo coordination chain assists energy band alignment and provides a redox‐active site, and the uncoordinated hydroxyl group contributes to the visible‐light absorptance, charge‐carrier transfer, and CO 2 ‐scaffold affinity. With a formic acid selectivity of 97.8 %, FeTCP‐OH‐Co affords CO 2 photoconversion with a reaction rate 4.3 and 15.7 times higher than those of FeTCP‐ Co and InTCP‐Co, respectively. These findings are also consistent with the spectroscopic study and DFT calculation.