Supercapacitive properties, optical band gap, and photoluminescence of CeO2-ZnO nanocomposites prepared by eco-friendly green and citrate sol-gel methods: A comparative study

CeO2-ZnO nanocomposite was synthesized using a cost-effective and environmentally friendly green method utilizing a natural extract of Hibiscus Sabdariffa L. The structural parameters, morphology, optical, and super capacitive properties of a novel green sol-gel synthesized CeO2-ZnO nanocomposite (CZO-g) were compared with those of a citrate sol-gel auto-combustion derived nanocomposite (CZO-s). XRD confirmed the formation of cubic and wurtzite hexagonal binary phases, and CZO-g exhibited better crystallinity than CZO-s. ZnO incorporation inhibits the accumulation of CeO2 semispherical NPs, as demonstrated by FESEM images. DRS and PL emission measurements confirmed that the optical band gap of nanocomposites was widened. CV, GCD and EIS measurements were used to determine the electrochemical supercapacitive behavior of nanomaterials deposited on Ni Foams in a 3 M KOH electrolyte. At a current density of 1 A g(-1), CZO-g exhibited significantly greater specific capacitance (431 F g(-1)) than CZO-s and CeO2-g. Furthermore, CZO-g retained 89.4% of its initial capacitance after 3000 cycles at a high current density of 7 A g(-1), indicating that it could be a promising candidate for a high-performance supercapacitor.

Automated summary

In this study, a CeO2-ZnO nanocomposite was synthesized using a green method and compared with a citrate sol-gel derived nanocomposite. The CZO-g exhibited better crystallinity and higher specific capacitance, indicating its potential as a high-performance supercapacitor material.