Studies on Photocatalytic CO2 Reduction over NH2-Uio-66(Zr) and Its Derivatives: Towards a Better Understanding of Photocatalysis on Metal–Organic Frameworks

Graphical Higher CO 2 photoreduction activity than previously studied metal–organic framework (MOF) NH 2 -MIL-125(Ti) in the presence of triethanolamine (TEOA) as the sacrificial agent under visible light is exhibited by the amino-functionalized MOF NH 2 -Uio-66(Zr). The photoinduced electron transfer from 2-aminoterephthalate linkers to Zr oxo clusters was revealed for the first time by photoluminescence studies, and the generated Zr III was detected by ESR analysis (see figure). Metal–organic framework (MOF) NH 2 -Uio-66(Zr) exhibits photocatalytic activity for CO 2 reduction in the presence of triethanolamine as sacrificial agent under visible-light irradiation. Photoinduced electron transfer from the excited 2-aminoterephthalate (ATA) to Zr oxo clusters in NH 2 -Uio-66(Zr) was for the first time revealed by photoluminescence studies. Generation of Zr III and its involvement in photocatalytic CO 2 reduction was confirmed by ESR analysis. Moreover, NH 2 -Uio-66(Zr) with mixed ATA and 2,5-diaminoterephthalate (DTA) ligands was prepared and shown to exhibit higher performance for photocatalytic CO 2 reduction due to its enhanced light adsorption and increased adsorption of CO 2 . This study provides a better understanding of photocatalytic CO 2 reduction over MOF-based photocatalysts and also demonstrates the great potential of using MOFs as highly stable, molecularly tunable, and recyclable photocatalysts in CO 2 reduction.