Highly efficient visible-light-driven CO2 reduction to formate by a new anthracene-based zirconium MOF via dual catalytic routes

Abstract

A new microporous robust zirconium metal–organic framework (Zr-MOF), NNU-28, has been synthesized and employed as a visible-light photocatalyst for carbon dioxide (CO₂) reduction to produce formate. NNU-28 is constructed by using a visible light responsive organic ligand derived from an anthracene group. Studies reveal that the as-prepared Zr-MOF shows desirable characteristics including excellent chemical and thermal stability, high CO₂ uptake, broad-band visible light absorption and efficient photoinduced charge generation. Remarkably, NNU-28 is highly efficient for visible-light-driven CO₂ reduction with a formate formation rate of 183.3 μmol h⁻¹ mmol_MOF⁻¹, which is among the highest performances of Zr-MOFs. Both photocatalytic experiments and electron paramagnetic resonance (EPR) studies reveal that both the inorganic building unit Zr₆ oxo cluster and the anthracene-based ligand contribute to the highly efficient photocatalysis of CO₂ reduction. The dual photocatalytic routes are demonstrated here to be more efficient for visible-light-driven CO₂ photoreduction than that typically relying on a ligand-to-metal charge transfer process, illustrating a new strategy to design and synthesize novel visible-light photocatalysts for CO₂ reduction with high efficiency.