Synergistic integration of ZrO₂-enriched reduced graphene oxide-based nanostructures for advanced photodegradation of...

The escalating demand for the antibiotic drug tetracycline hydrochloride (TCH) contributes to an increased release of its residues into land and water bodies, which poses risks to both aquatic life and human health. Therefore, it is precedence to effectively degrade TCH residues to protect environment from their long-term impacts. In this aspect, the present study entails the synthesis of zirconia (ZrO₂) nanostructures and focuses on the enhancement in the catalytic performance of ZrO₂ nanostructures by employing reduced graphene oxide (RGO) as a solid support to synthesize ZrO₂-enriched RGO-based photocatalysts (ZrO₂-RGO) for the degradation of TCH. The study delves into comprehensive spectroscopic and microscopic investigations and their photodegradation assessments. Powder XRD and HR-TEM studies depicted the phase crystallinity and also displayed uniform distribution of ZrO₂ nanostructures with spherical morphology within ZrO₂-RGO. This corresponds to high surface-to-volume ratios, providing a substantial number of active sites for light absorption and generation of e^--h⁺ pairs. Moreover, the heterojunctions created between RGO and ZrO₂ nanostructures promoted the interspecies electron transfer which prolonged the recombination time of e^- and h⁺ than pure ZrO₂ nanostructures, accounted for enhanced degradation of TCH using ZrO₂-RGO. The photocatalytic activity of as-synthesized materials were examined under visible and UV light irradiation. The degradation efficiency of ~ 73.82% was achieved using ZrO₂-RGO-based photocatalyst with rate constant k = 0.007023 min^-1 under visible-light illumination. Moreover, under UV-light, the degradation rate was explicated to be k = 0.01017 min^-1 with ~ 85.56% degradation of TCH antibiotics within 180 mins. Hence, the synthesized ZrO₂-enriched RGO-based photocatalysts represents a promising potential for the effective degradation of pharmaceutical compounds, particularly TCH under visible and UV-light irradiation.