2D g-C3N4 nanosheets functionalized with nickel-doped ZrO2 nanoparticles for synergistic photodegradation of toxic chemical pollutants

The photocatalytic removal of toxic chemical pollutants from wastewater has garnered significant attention in recent times owing to its notable removal efficiency, cost-effectiveness, and eco-friendly characteristics. Nonetheless, this catalytic process necessitates augmented charge separation and distinctive interface properties to facilitate catalytic reactions for water treatment applications. Therefore, in the current study, novel g-C3N4/Ni-doped ZrO2 heterostructured hybrid catalysts have been synthesized via a hydrothermal approach. Microscopic studies reveal that ZrO2 nanospheres were distributed on the layered-like 2D structure of g-C3N4 nanosheets. Electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (UV-DRS), and photoluminescence (PL) characterizations were employed to investigate the impact of bandgap, electron-hole recombination, charge transfer, and interface properties on the catalytic performance of g-C3N4/ZrO2 hybrids. XRD analysis confirmed that the Ni-ions do not disturb the host lattice crystal structure and heterostructure development between g-C3N4 and doped ZrO2 sample. Structurally, Ni-doped nanoparticles were found to be equally superficially dispersed on g-C3N4 sheets. Optical analysis results suggest that the hybrid catalyst possesses a narrow bandgap of 2.56 eV. The synthesized photocatalyst degraded rhodamine B (RhB) and tetracycline (TC) with ∼92% and ∼89% degradation efficiency, respectively. Heterostructured hybrid catalysts showed superior degradation rate constants than other catalysts. This might be attributed to the sufficient separation of electron-hole due to the development of a heterojunction. The radical scavenging experiments suggested that O2●- and ●OH radicals contributed substantially to the dye elimination activity of the composite. Therefore, the synthesized novel nanohybrid catalysts in this study present an efficient and straightforward synthesis method for the efficient removal of toxins from wastewater under visible light irradiation.