Selective CO2 photoreduction into CO over Ti3C2 quantum dots decorated NH2-MIL-101(Fe) heterostructures

Exploring effective photocatalyst to promote the conversion of CO2 into valuable chemical fuels remains a great challenge. Herein, a novel heterostructure, namely Ti3C2 quantum dots (QDs) decorated NH2-MIL-101(Fe), was designed and fabricated via an electrostatic adsorption method. The resultant heterostructure exhibited remarkably improved activity for CO2 photoreduction under visible-light illumination. The optimal NH2-MIL-101(Fe)@Ti3C2 QDs catalyst with 0.75 wt% Ti3C2 QDs achieved a CO-evolution rate of 55.7 μmol h−1 g−1, which was 2.6 times greater than that of pristine NH2-MIL-101(Fe). The enhanced activity of NH2-MIL-101(Fe)@Ti3C2 QDs was mainly due to the extended visible-light response and the effective charge separation and transfer benefiting from the formation of a Schottky junction at the interface. Isotope-labeling experiment indicated that CO was produced from CO2. Finally, the reaction intermediates and mechanism of photocatalytic CO2 reduction were investigated by in-situ FT-IR.