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

Abstract

Metal–organic frameworks (MOFs) could be a promising class of photocatalysts due to their high surface area, framework robustness, and tunable architectures, which enable modulation of 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 exhibited remarkably enhanced photocatalytic activity compared to the Co-based photosensitizer. This 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-MOF-mediated photodegradation. We further illustrate the importance of hydrogen bonding-assisted encapsulation of an antibiotic molecule 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 complete photodegradation of antibiotics.