Visible light driven hydrogen bonding assisted complete photocatalytic degradation of selected antibiotics by lanthanidebased metal-organic frameworks

Abstract

Metal-organic frameworks (MOFs) could be a promising class of photocatalysts owing to their high surface area, framework robustness, and tunable architectures that allow for modulating their semiconductor properties for enhanced light harvesting and subsequent photocatalysis. In this work, a cobalt-based metalloligand has been utilized to synthesise lanthanide (Ln)-based MOFs (Ln-MOFs). The architecturally engineered Ln-MOFs exhibit significant visible light absorption and support noteworthy photocatalysis for the complete degradation of the selected antibiotics. Both Ln-MOFs enabled complete photodegradation of antibiotics, as supported by their high degradation reaction rates. The Ln-MOFs displayed remarkably enhanced photocatalytic activities when compared to the Co-based photosensitizer. Such a fact is attributed to an enhanced charge-carrier lifetime for both Ln-MOFs, which was corroborated by the transient absorption spectroscopy, photoluminescence, and electrochemical impedance spectroscopy analyses. These studies, along with the scavenger experiments, helped in establishing the probable mechanism for Ln-MOFs-mediated photodegradation. We further illustrate the importance of hydrogen bonding-assisted encapsulation of an antibiotic within the pores of Ln-MOFs, which remarkably improved its photocatalytic degradation. The present visible light-driven Ln-MOFs are a rare example of photocatalysts exhibiting high efficiency for the photodegradation of antibiotics.