NH 2 ‐Functionalization of MIL‐125 (Ti) for Boosted Visible‐Light Photocatalytic CO 2 to CO

ABSTRACT Photocatalytic CO 2 reduction technology is regarded as an effective approach to achieve carbon neutrality. As a type of metal–organic framework (MOF), MIL‐125 (Ti) is well‐known for its stable structure and tunable electronic structure, which is widely studied in the field of photocatalysis. In this work, a series of amino‐functionalized MIL‐125 (Ti) with different amino concentrations was systematically prepared by the solvothermal method to investigate their photocatalytic CO 2 reduction activity. The electronic structure, charge transfer efficiency, and band gap of all the prepared samples have been systematically studied by using a series of characterization methods. Characterization results indicated that the introduction of amino groups into MIL‐125 (Ti) can reduce the bandgap and enhance its light absorption capacity, thereby improving the photocatalytic CO 2 reduction to CO activity. Compared with the pristine MIL‐125 (Ti), the amino (NH 2 )‐modified samples exhibited excellent yield for CO 2 ‐to‐CO conversion. The optimal sample achieved a maximum CO yield of 85.7 µmol/g, which is 13.2 times that of MIL‐125 (Ti). Furthermore, the introduction of NH 2 enhances the crystallinity of MIL‐125 (Ti), which is conducive to charge transfer and suppresses the recombination of electron‐hole pairs, further improving the electron utilization efficiency.