Synthesis of nanohybrids of polycarbazole with α-MnO₂ derived from Brassica oleracea: a comparison of photocatalytic degradation of an antibiotic drug under microwave and UV irradiation

The present work describes the synthesis of α-MnO₂ nanorods using a natural extract of Brassica oleracea (cabbage) and the formulation of its nanohybrids with polycarbazole, i.e., α-MnO₂/PCz. Synergistic interaction between PCz and MnO₂ is revealed from infrared spectroscopy (IR) studies while the composition is determined by X-ray photoelectron spectroscopy (XPS). The formation of α-MnO₂ nanorods is confirmed via high-resolution transmission electron microscopy (HRTEM). The indirect bandgap of α-MnO₂ is reported as 2.5 eV while for the nanohybrids it is found to be ranging between 2.3 and 2.5 eV. Results show that 91% and 89% of degradation is achieved within 30 min and 90 min under the microwave and UV irradiation respectively. Hydroxyl radicals (^•OH) and superoxide (^•O₂⁻) radicals are responsible for photocatalytic degradation of the drug Bactrim DS which is confirmed by radical scavenging experiments. The nanohybrids show promising catalytic activity under UV as well as microwave irradiation.