Locking Photosensitizers into Staggered-Stacking and DNA-Interlocked Metal–Organic Frameworks for Outstanding CO 2 Photoreduction Activity

Photosensitizers (PSs) play crucial roles in photocatalysis by efficiently harvesting light and facilitating photoinduced charge transfer. However, whether they are applied in a homogeneous solution or immobilized on catalysts, PSs are prone to deactivation through leaching or desorption, leading to a significant decline in photocatalytic performance. Herein, two highly photoactive metal–organic frameworks (MOFs) denoted as NWUM-Cd- s and NWUM-Cd were constructed from Cd(II) ions, 4,4′,4′′-nitrilotribenzoic acid (H 3 TCA), and a classic [Ru(bpy) 3 ] 2+ PS via cocrystallization. These MOFs can firmly lock the [Ru(bpy) 3 ] 2+ PS through the structural characteristics of DNA-like double-helix and “···ABABA···” dislocation stacking. This prevents the PS from deactivating during the photocatalytic process, which enables these MOFs to exhibit excellent photocatalytic activity and long-term cycling stability in the model CO 2 photoreduction reaction. The CO production rate of interpenetrated NWUM-Cd- s (13.9 mmol g –1 h –1 ) is 5.3 times that of dislocated monolayer NWUM-Cd (2.6 mmol g –1 h –1 ). In situ characterizations and theoretical calculations reveal that the interpenetrated structure of NWUM-Cd- s significantly enhances the separation of photogenerated charges, which in turn reduces the overall reaction energy barrier and promotes electron–proton transfer cooperativity, thus leading to more outstanding photoactivity than that of NWUM-Cd . This work demonstrates unprecedented staggered stacking and DNA-like interlocking strategies to lock PSs in catalysts, thereby tackling the long-standing challenges in traditional photocatalysis of low light utilization efficiency, PS deactivation, and slow charge transfer.