Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Feb 21;27(4):1442.
doi: 10.3390/molecules27041442.

Synthesis and Characterization of an α-Fe2O3-Decorated g-C3N4 Heterostructure for the Photocatalytic Removal of MO

Rooha Khurram  1 , Zaib Un Nisa  2 , Aroosa Javed  3 , Zhan Wang  1 , Mostafa A Hussien  4   5
Affiliations

Synthesis and Characterization of an α-Fe2O3-Decorated g-C3N4 Heterostructure for the Photocatalytic Removal of MO

Rooha Khurram et al. Molecules. .

Abstract

This study describes the preparation of graphitic carbon nitride (g-C3N4), hematite (α-Fe2O3), and their g-C3N4/α-Fe2O3 heterostructure for the photocatalytic removal of methyl orange (MO) under visible light illumination. The facile hydrothermal approach was utilized for the preparation of the nanomaterials. Powder X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX), and Brunauer-Emmett-Teller (BET) were carried out to study the physiochemical and optoelectronic properties of all the synthesized photocatalysts. Based on the X-ray photoelectron spectroscopy (XPS) and UV-visible diffuse reflectance (DRS) results, an energy level diagram vs. SHE was established. The acquired results indicated that the nanocomposite exhibited a type-II heterojunction and degraded the MO dye by 97%. The degradation ability of the nanocomposite was higher than that of pristine g-C3N4 (41%) and α-Fe2O3 (30%) photocatalysts under 300 min of light irradiation. The formation of a type-II heterostructure with desirable band alignment and band edge positions for efficient interfacial charge carrier separation along with a larger specific surface area was collectively responsible for the higher photocatalytic efficiency of the g-C3N4/α-Fe2O3 nanocomposite. The mechanism of the nanocomposite was also studied through results obtained from UV-vis and XPS analyses. A reactive species trapping experiment confirmed the involvement of the superoxide radical anion (O2•-) as the key reactive oxygen species for MO removal. The degradation kinetics were also monitored, and the reaction was observed to be pseudo-first order. Moreover, the sustainability of the photocatalyst was also investigated.

Keywords: MO photodegradation; alignment of energy levels; g-C3N4; g-C3N4/α-Fe2O3 nanocomposite; heterostructure (type-II).

PubMed Disclaimer

Conflict of interest statement

The authors declare that there is no conflict of interest.

Figures

Figure 1
Figure 1
The XRD patterns.
Figure 2
Figure 2
SEM micrographs of (a) α-Fe2O3 agglomerated nanoparticles, (b) g-C3N4 crumpled nanosheet, and (c) g-C3N4/α-Fe2O3 nanosheet well decorated with nanoparticles.
Figure 3
Figure 3
EDS spectra of: (a) g-C3N4, (b) α-Fe2O3, and (c) g-C3N4/α-Fe2O3 with quantification of atomic percentages.
Figure 4
Figure 4
XPS spectra of g-C3N4/α-Fe2O3 nanocomposite: (a) C (1s), (b) N (1s), (c) Fe (2p), and (d) O (1s).
Figure 4
Figure 4
XPS spectra of g-C3N4/α-Fe2O3 nanocomposite: (a) C (1s), (b) N (1s), (c) Fe (2p), and (d) O (1s).
Figure 5
Figure 5
(a) N2 adsorption–desorption isotherms and (b) pore size distributions of α-Fe2O3, g-C3N4, and α-Fe2O3/g-C3N4 samples.
Figure 5
Figure 5
(a) N2 adsorption–desorption isotherms and (b) pore size distributions of α-Fe2O3, g-C3N4, and α-Fe2O3/g-C3N4 samples.
Figure 6
Figure 6
UV-vis absorption spectral changes of MO with time in (a) pure g-C3N4 and (b) g-C3N4/α Fe2O3 nanocomposite under light illumination.
Figure 7
Figure 7
(a) Plot of C/Co vs. time. (b) The corresponding degradation efficiency of MO removal. (c) Plot of ln (C/Co) vs. time.
Figure 7
Figure 7
(a) Plot of C/Co vs. time. (b) The corresponding degradation efficiency of MO removal. (c) Plot of ln (C/Co) vs. time.
Figure 8
Figure 8
XPS valence band spectra with insets representing magnified spectra of (a) g-C3N4 and (b) α-Fe2O3, and absorbance spectra with insets representing the Tauc plots for (c) g-C3N4 and (d) α-Fe2O3.
Figure 8
Figure 8
XPS valence band spectra with insets representing magnified spectra of (a) g-C3N4 and (b) α-Fe2O3, and absorbance spectra with insets representing the Tauc plots for (c) g-C3N4 and (d) α-Fe2O3.
Figure 9
Figure 9
(a) Alignment of energy levels in the g-C3N4/α-Fe2O3 nanocomposite. (b) Role of radical scavengers on MO photodegradation over g-C3N4/α-Fe2O3 nanocomposite.
Figure 10
Figure 10
g-C3N4/α-Fe2O3 nanocomposite stability.
Figure 11
Figure 11
Chemical structure of MO dye.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Tkaczyk A., Mitrowska K., Posyniak A. Synthetic organic dyes as contaminants of the aquatic environment and their implications for ecosystems: A review. Sci. Total Environ. 2020;717:137222. doi: 10.1016/j.scitotenv.2020.137222. - DOI - PubMed
    1. Chang J.-S., Lin C.-Y. Decolorization kinetics of a recombinant Escherichia coli strain harboring azo-dye-decolorizing determinants from Rhodococcus sp. Biotechnol. Lett. 2001;23:631–636. doi: 10.1023/A:1010306114286. - DOI
    1. Bai Y.-N., Wang X.-N., Zhang F., Wu J., Zhang W., Lu Y.-Z., Fu L., Lau T.-C., Zeng R.J. High-rate anaerobic decolorization of methyl orange from synthetic azo dye wastewater in a methane-based hollow fiber membrane bioreactor. J. Hazard. Mater. 2020;388:121753. doi: 10.1016/j.jhazmat.2019.121753. - DOI - PubMed
    1. Haque M.M., Haque M.A., Mosharaf M.K., Marcus P.K. Decolorization, degradation and detoxification of carcinogenic sulfonated azo dye methyl orange by newly developed biofilm consortia. Saudi J. Biol. Sci. 2021;28:793–804. doi: 10.1016/j.sjbs.2020.11.012. - DOI - PMC - PubMed
    1. Kant R. Textile dyeing industry an environmental hazard. Nat. Sci. 2011;4:17027. doi: 10.4236/ns.2012.41004. - DOI

LinkOut - more resources