Photoconductive network structured copper oxide for simultaneous photoelectrocatalytic degradation of antibiotic (tetracycline) and bacteria (E. coli)

- Highly photoconductive copper oxide networks were synthesized.
- Tetracycline degradation is higher in photoelectrocatalysis than photocatalysis.
- Synergistic degradation of both antibiotic and bacteria was performed together.
- Cyclic network model was developed and validated for the reaction mechanism.

As microbes develop resistance towards antibiotics, it is important to eliminate both from waste water streams simultaneously. Though photocatalysis is effective, complete removal can be achieved faster using photoelectrocatalysis (PEC) using photoconductive materials. Based on this idea, we have developed a network structured, high photoconductive copper oxide using solution combustion method. Various characterizations such as XRD, DRS, SEM, TEM, PL, XPS have been performed for a meticulous study of structural, optical, morphological and oxidation properties, respectively. CuO synthesized in this study possesses band gap of 2.1 eV, monoclinic structure, low recombination of charge carriers and shows much higher catalytic activity than copper oxide nano rods reported in the literature. Both antibiotics and bacteria have been simultaneously degraded via PEC. PEC exhibited a threefold higher rate of antibiotic degradation compared to photocatalysis. Reactive radical species such as electrons and superoxide radicals were illustrated to play a key role in accelerating the process of degradation. Notably, CuO-CSA was stable even after 10 cycles of reusability. A detailed mechanism of degradation PEC was developed and the cyclic network model was proposed for validation of the series of reactions. The degradation rate coefficients were obtained from this model. This work has important implications in the area of PEC for antibiotic and bacterial degradation.

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