Optical, photocatalytic, electrochemical, and magnetic applications of co-precipitation-assisted ZnO@graphite nanocomposites

In the current study, ZnO@graphite nanocomposites were synthesized using an easy co-precipitation route to develop multifunctional properties suitable for assessing energy storage, optoelectronic, photocatalysis, and magnetic applications. Structural characterizations (XRD, SEM, TEM, EDX, and XPS) of the synthesized composite
confirmed the strong interfacial interaction between the ZnO and graphite composite with good crystallinity and
composed of heterogeneous particle morphology. Nitrogen adsorption–desorption studies demonstrated a mesoporous structure. The UV–visible spectrum of ZnO@graphite showed a strong ultraviolet absorption edge at
370 nm as well as confirming the band gap value to be 3.06 eV. Visible luminescence peaks were detected in the
recorded PL spectrum of the ZnO@graphite, which is caused by the presence of oxygen vacancies and interfacial
defects. The photodegradation performance of three different dyes (Acridine orange (AO), Congo red (CR), and
Alizarin red (AR)) along with the synthesized composite as a photocatalyst under the illumination of UV light
was comparatively discussed in detail. Among the dyes, acridine orange was found to be effective for photodegradation efficiency (99.8%) with shorter time intervals (150 min) than the other two dyes (Congo red
(95.8%) for 180 min and Alizarin red (51.9% for 210 min)). Electrochemical property response (oxidation/reduction, specific capacitance and electrical transport) of the ZnO@graphite at various scan rates (10–200 mVs
−1were scrutinized with the assistance of cyclic voltammetry and electrochemical impedance measurement. The
electrochemical measurement results demonstrated pseudocapacitive behaviour. Using PPMS measurement, the
synthesized nanocomposite confirmed a weak ferromagnetic behaviour at room temperature.