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. 2024 Mar 19;14(1):6606.
doi: 10.1038/s41598-024-54905-0.

Antibacterial and sunlight-driven photocatalytic activity of graphene oxide conjugated CeO2 nanoparticles

Fauzia  1 , Mo Ahamad Khan  2 , Mohd Chaman  3 , Ameer Azam  4   5
Affiliations

Antibacterial and sunlight-driven photocatalytic activity of graphene oxide conjugated CeO2 nanoparticles

Fauzia et al. Sci Rep. .

Abstract

This work focuses on the structural, morphological, optical, photocatalytic, antibacterial properties of pure CeO2 nanoparticles (NPs) and graphene oxide (GO) based CeO2 nanocomposites (GO-1/CeO2, GO-5/CeO2, GO-10/CeO2, GO-15/CeO2), synthesized using the sol-gel auto-combustion and subsequent sonication method, respectively. The single-phase cubic structure of CeO2 NPs was confirmed by Rietveld refined XRD, HRTEM, FTIR and Raman spectroscopy. The average crystallite size was calculated using Debye Scherrer formula and found to increase from 20 to 25 nm for CeO2 to GO-15/CeO2 samples, respectively. The related functional groups were observed from Fourier transform infrared (FTIR) spectroscopy, consistent with the outcomes of Raman spectroscopy. The optical band gap of each sample was calculated by using a Tauc plot, which was observed to decrease from 2.8 to 1.68 eV. The valence state of Ce (Ce3+ and Ce4+) was verified using X-ray photoelectron spectroscopy (XPS) for CeO2 and GO-10/CeO2. The poisonous methylene blue (MB) dye was used to evaluate the photocatalytic activity of each sample in direct sunlight. The GO-15/CeO2 nanocomposite showed the highest photocatalytic activity with rate constant (0.01633 min-1), and it degraded the MB dye molecules by 100% within 120 min. The high photocatalytic activity of this material for degrading MB dye establishes it as an outstanding candidate for wastewater treatment. Further, these nanocomposites also demonstrated excellent antimicrobial activity against Pseudomonas aeruginosa PAO1.

Keywords: Antibacterial activity; Cerium oxide; Graphene oxide; Nanocomposite; Photocatalytic activity; Sonication.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
(a) Rietveld refined XRD spectrum of CeO2 NPs. (b) XRD spectra of CeO2 NPs and GO (1, 5, 10 and 15 wt %) based CeO2 nanocomposite.
Figure 2
Figure 2
FTIR spectra of pure CeO2 NPs and GO (1, 5, 10 and 15 wt.%) based nanocomposite.
Figure 3
Figure 3
Raman spectra (a) for CeO2 NPs and (b) GO (10 wt.%) based CeO2 nanocomposite.
Figure 4
Figure 4
(a,e) TEM images, (b,f) HRTEM fringe micrographs, (c,g) SAED graphs of pure CeO2 NPs and GO (10 wt.%) based CeO2 nanocomposite, respectively and (d,h) Gaussian fitting of particle size distribution.
Figure 5
Figure 5
SEM images for (a) pure CeO2 NPs and (b) GO (10 wt.%) based CeO2 nanocomposite. EDS spectra for (c) pure CeO2 NPs and (d) GO (10 wt.%) based CeO2 nanocomposite.
Figure 6
Figure 6
(a) UV–vis absorbance spectra of all synthesized materials. (b) Tauc plot for energy band gap calculation of each sample.
Figure 7
Figure 7
XPS (a) full scan spectrum, narrow scan spectra of (b) Ce 3d, (c) O 1 s and (d) C 1 s energy level of CeO2 NPs.
Figure 8
Figure 8
XPS (a) full scan spectrum, narrow scan spectra of (b) Ce 3d, (c) O 1 s and (d) C 1 s energy level of GO (10 wt.%) based CeO2 nanocomposite.
Figure 9
Figure 9
Absorbance spectra of MB dye after wastewater treatment in the presence of sunlight with photocatalyst (a) pure CeO2 (b) GO based (1 wt.%) CeO2 (c) GO based (5 wt.%) CeO2 (d) GO based (10 wt.%) CeO2 and (e) GO based (15 wt.%) CeO2, respectively.
Figure 10
Figure 10
Mechanism of photodegradation of MB dye using synthesized materials.
Figure 11
Figure 11
(a) C/Co vs time spectra for pure CeO2 NPs and GO (1, 5, 10 and 15 wt.%) based CeO2, and (b) Bar diagram of percent degradation vs GO concentration for all synthesized materials.
Figure 12
Figure 12
Reaction rate constant for the photocatalysts (a) pure CeO2 (b) GO (1 wt.%) based CeO2 (c) GO (5 wt.%) based CeO2 (d) GO (10 wt.%) based CeO2 and (e) GO (15 wt.%) based CeO2.
Figure 13
Figure 13
Antibacterial activity of nanoparticles against Pseudomonas aeruginosa PAO1.
See this image and copyright information in PMC

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