Solvent-Free Photoreduction of CO to CO Catalyzed by Fe-MOFs with Superior Selectivity.

It is deemed as a desired approach to utilize solar energy for the conversion of CO into valuable products, and the majority of the MOFs-based photocatalytic reductions of CO have focused on formic acid (HCOOH) production with an organic solvent as the reaction medium. Herein, we report a solvent-free reaction route for the photoreduction of CO catalyzed by Fe-MOFs, namely, NH-MIL-53(Fe) [(Fe(OH)(NH-BDC)]•G, NH-MIL-88B(Fe) [FeO(HO)(NH-BDC)]Cl•G, and NH-MIL-101(Fe) [FeO(HO)(NH-BDC)]Cl•G (NH-BDC = 2-aminoterephthalic acid; G = guest and/or solvent molecules). Compared with the orthodox reaction route, the present out-of-the-way photocatalytic reduction of CO with superior selectivity to CO occurs at the gas-solid interface. The reaction procedure is environmentally friendly and provides a possibility to address the CO emission problem. Importantly, NH-MIL-101(Fe) shows the highest photocatalytic activity among these Fe-MOFs due to its efficient charge separation and electron transfer.