Enhancing the Photocatalytic Activity of Zirconium-Based Metal–Organic Frameworks Through the Formation of Mixed-Valence Centers

Despite the desirability of metal–organic frameworks (MOFs) as heterogeneous photocatalysts, current strategies available to enhance the performance of MOF photocatalysts are complicated and expensive. Herein, a simple strategy is presented for improving the activity of MOF photocatalysts by regulating the atomic interface structure of the metal active sites on the MOF. In this study, MOF (PCN-222) is hybridized with cellulose acetate (CA@PCN-222) through an optimized atomic interface strategy, which lowers the average valence state of Zr ions. The electronic metal-support interaction mechanism of CA@PCN-222 is revealed by evaluating the photocatalytic CO₂ reduction reaction (CO₂RR). The experimental results suggested that the electron migration efficiency at the atomic interface of the MOFs strongly coupled with cellulose is significantly improved. In particular, the CO₂RR to formate activity of CA@PCN-222 photocatalyst greatly increased from 778.2 to 2816.0 µmol g⁻¹ compared with pristine PCN-222 without cellulose acetate. The findings suggest that the strongly coupled metal–ligand moiety at the atomic interface of MOFs may play a synergistic role in heterogeneous catalysts.