Facile Synthesis of Carbon Dot Deposited γ-FeOOH Nanosheet/Polypyrrole Composite: A Robust Photocatalyst for Degradation of Antibiotics under Sunlight Irradiation with Enhanced Antibacterial Activity
Abanindra Nath Sarkar, Satyajeet Padhi, Soni Kumari, Sheeja Jagadevan, Sagar Pal
Abstract
This work reports the fabrication of a nanocomposite using carbon dot-deposited γ-FeOOH/polypyrrole composite through a facile in situ growth of γ-FeOOH, polymerization of pyrrole, and deposition of carbon dots (CDs) in a single pot along with its application as a photocatalyst toward degradation of antibiotics under sunlight irradiation. Here, the expired pharmaceutical drugs (waste) were used as a source of the synthesis of CDs to realize a “waste-to-wealth” approach. A series of nanocomposites (PFL/CDs- x; x = 1, 2, 3, and 4) with different γ-FeOOH content have been synthesized, and their photocatalytic activity was studied. Among all composites, PFL/CDs-2 exhibited the highest degradation efficiency of 97% within 90 min. The optimized γ-FeOOH and CD content in PFL/CDs-2 enhanced light trapping, charge separation, surface area, and formation of distinct heterojunction, indicating it as a promising candidate in photocatalysis. The excellent photocatalytic activity of PFL/CDs-2 can be attributed to synergistic enhancement of the light harvesting due to slow photon effect of the γ-FeOOH nanosheet and the inhibited recombination rate of photoexcited charge carriers based on a Z-scheme photocatalytic mechanism. In addition, the antibacterial potential of the synthesized nanocomposite was studied against Bacillus pumilus (Gram-positive) and Escherichia coli (Gram-negative) bacteria. Moreover, the PFL/CDs-2 composite was found to be magnetically separable and recycled without a significant loss of photocatalytic efficiency after four cycles, indicating the high reusability and stability of the photocatalyst.