Boosting the photocatalytic hydrogen evolution and NO removal via synergistic effects of in-situ Pt NPs formation and titanium integration in Zr-Porphyrin MOFs

Abstract

An efficient bifunctional porphyrin-based MOF is fabricated for photocatalytic hydrogen evolution and NO removal, in which the mixed Zr/Ti-oxo clusters are the metal nodes and uniformly distributed Pt nanoparticles (Pt NPs) are the co-catalysts. It is worth noting that the optimal Zr-MOF-s(Pt)(Zr/Ti)-R is obtained through replacing partial Zr(IV) with Ti(IV) in the original Zr-based porphyrin MOFs and in-situ generating confined Pt NPs with a relatively small size within the internal cavities. Compared with the majority of reported Zr-based porphyrin MOFs, the Zr-MOF-s(Pt)(Zr/Ti)-R exhibits an extremely high hydrogen evolution activity (2545.11 μmol·g−1·h−1) and NO removal rate (46.6 %) under visible light irradiation. The excellent photocatalytic performance should be ascribed to the reason that the mixed Zr/Ti-oxo cluster and the in-situ generated Pt NPs significantly promote the rate of charge transfer and separation. Moreover, the photocatalytic NO oxidation process was also monitored by in-situ DRIFTS, which indicates the Zr-MOF-s(Pt)(Zr/Ti)-R could realize the effective oxidation of NO and intermediates to the final product (NO3–). This work provides us with a practical route to further improve the photocatalytic performance by synergistically modifying the original metal clusters to adjust the ligand-to-metal charge transfer efficiency and in-situ introducing metal nanoparticles to form Schottky junctions.