Co-adsorption and Fenton-like oxidation in the efficient removal of methylene blue by MIL-88B@UiO-66 nanoflowers

Development of binary MOF-on-MOF heterostructures is a research hotspot in MOFs chemistry due to the advantages elicited by a closely connected interface, which may endow more abundant functionality and even broader applications in interface chemistry. A MOF-on-MOF heterostructure was constructed by in situ growth of MIL-88B on the outer surface of UiO-66. The resultant MIL-88B@UiO-66 produced had an interesting flower-like morphology composed of MIL-88B (petal) on tetrahedral UiO-66 (core). The MIL-88B@UiO-66 heterostructure showed adsorption and Fenton-like oxidation abilities, with distinctly improved structural stability in aqueous solution compared with that of single MIL-88B. Methylene blue (MB) was selected as the target molecule to evaluate the adsorption and Fenton-like oxidation activities. The efficiency of total removal of MB was studied systematically under various operating conditions and the influencing factors were optimized. The kinetics of adsorption and catalytic oxidation were simulated to explore the interactions between MB and MIL-88B@UiO-66. The mechanisms of enhanced adsorption and Fenton-like oxidation were suggested. The cyclic removal performance and structural stability of MIL-88B@UiO-66 were also determined.

Automated summary

The development of binary MOF-on-MOF heterostructures is a hot topic in MOFs chemistry, offering advantages of a closely connected interface for enhanced functionality and broader applications in interface chemistry. In this study, a MOF-on-MOF heterostructure was created by in situ growth of MIL-88B on the outer surface of UiO-66, resulting in a flower-like morphology composed of MIL-88B petals on a tetrahedral UiO-66 core. The MIL-88B@UiO-66 heterostructure exhibited improved adsorption and Fenton-like oxidation abilities, as well as enhanced structural stability in aqueous solution compared to single MIL-88B.