Encapsulation of in-situ generated g-CNQDs with up-conversion effect in Zr/Ti-based porphyrin MOFs for efficient photocatalytic hydrogen production and NO removal

In this study, a highly efficient bifunctional porphyrin-based MOFs with uniformly in-situ generated g-C 3 N 4 quantum dots (g-CNQDs) was fabricated for photocatalytic hydrogen evolution and NO removal, in which PtTCPP as the organic ligand and mixed Zr/Ti-oxo clusters as the metal nodes. Compared with most reported Zr-based porphyrin MOFs, the g-CNQDs@Zr-MOFs(Pt)(Zr/Ti) exhibited outstanding hydrogen evolution activity (14511.57 μmol g −1 ) and NO removal rate (31.9 %) under visible light irradiation. The obviously improved photocatalytic performance could be attributed to the significantly enhanced charge separation and transfer rates by the mixed Zr/Ti-oxo clusters via the rapid Ti 3+ /Ti 4+ process. Moreover, the uniformly in-situ generated g-CNQDs via confinement effect in the cavity of MOFs could also improve the utilization of visible light especially through the up-conversion effect, and promote charge carriers separation. This work provides an idea for us to expand the scope of light utilization and promote charge transfer and separation rates of MOFs via functionalizing host MOFs matrix and coupling guest active species to improve photocatalytic performance further.