Synergistic effect of nano-floret CeO2/ZnO nanocomposite as an efficient photocatalyst for environmental remediation

In this study, pure CeO2, ZnO, and CeO2/ZnO nanocomposite (CZ-NC) were synthesized using solution combustion method using urea as a fuel. The physical properties of the as-prepared samples were investigated using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV–vis) spectroscopy, photoluminescence (PL) spectroscopy, Raman spectroscopy, and Brunauer-Emmett-Teller (BET) analysis. X-ray diffraction peak confirmed the successful fabrication and structural parameters of the nanomaterials. FTIR and Raman analyses confirmed the presence of Ce–O and Zn–O vibrational modes, respectively. The energy band gap (Eg) of CZ-NC estimated from the UV–vis spectra has narrowed to 1.88 eV, which enhanced the photocatalytic activity. The weak PL intensity peaks implied a lower charge recombination rate with maximum charge separation, facilitating more radical generation. BET analysis has confirmed the nanomaterial's large surface area and mesoporous nature. FESEM was used to investigate the surface morphologies of the nanomaterials, which displayed beautiful florets and sheet morphologies for CZ-NC. The internal structure of the nanomaterials was analyzed using HRTEM. EDAX further confirmed the purity of the nanomaterials, and homogeneous dispersion of elements was observed by EDX mapping. Antibacterial and dye-degradation experiments were conducted to understand the photocatalytic activities of the samples. The antibacterial activity of CZ-NC against both gram-positive and gram-negative bacteria was superior to that of pure nanoparticles. Methylene blue (MB) dye was used to evaluate the degradation efficiency. The maximum degradation efficiency of 97.10 % was achieved for CZ-NC under a visible light source for 120 min. This enhanced activity can be attributed to the Advanced Oxidation Process (AOP).