Metal-coordinated porphyrin COFs enable efficient visible-light-driven photocatalytic NADH regeneration

Abstract

We present three porphyrin-based covalent organic frameworks (COFs), Por-BPy-COF1, Por-RhBPy-COF2, and ZnPor-RhBPy-COF3, synthesized as visible-light-responsive photocatalysts for NADH regeneration. These COFs incorporate porphyrin units that absorb visible light across a broad spectrum (200–680 nm), with Por-RhBPy-COF2 and ZnPor-RhBPy-COF3 further enhanced by rhodium and zinc metal coordination to promote charge separation. Notably, the rhodium-coordinated COFs (Por-RhBPy-COF2 and ZnPor-RhBPy-COF3) exhibited significantly higher catalytic activity (∼41–46% in 1 hour) compared to Por-BPy-COF1 (2.6%), attributed to rhodium's bioinspired role in facilitating NAD⁺ reduction. Structural stability and sustained catalytic performance were confirmed, with Por-RhBPy-COF2 maintaining >37% activity during a 1-hour cyclic NADH regeneration test. These findings highlight the potential of these COFs for efficient solar-to-chemical energy conversion, advancing sustainable photocatalytic technologies.