A1 Journal article (refereed)
Sub-level engineering strategy of nitrogen-induced Bi2O3/g-C3N4 : a versatile photocatalyst for oxidation and reduction (2021)

Khazaee, Z., Mahjoub, A. R., Khavar, A. H. C., Srivastava, V., & Sillanpää, M. (2021). Sub-level engineering strategy of nitrogen-induced Bi2O3/g-C3N4 : a versatile photocatalyst for oxidation and reduction. Environmental Science and Pollution Research, 28(36), 50747-50766. https://doi.org/10.1007/s11356-021-14308-4

JYU authors or editors

Publication details

All authors or editors: Khazaee, Zeynab; Mahjoub, Ali Reza; Khavar, Amir Hossein Cheshme; Srivastava, Varsha; Sillanpää, Mika

Journal or series: Environmental Science and Pollution Research

ISSN: 0944-1344

eISSN: 1614-7499

Publication year: 2021

Publication date: 10/05/2021

Volume: 28

Issue number: 36

Pages range: 50747-50766

Publisher: Springer

Publication country: Germany

Publication language: English

DOI: https://doi.org/10.1007/s11356-021-14308-4

Publication open access: Not open

Publication channel open access:

Abstract

Herein, the α-Bi2O3 nanocrystal decorated by nitrogen dopant and its heterojunction nanocomposite with g-C3N4 (N0.1/Bi2O3/g-C3N4) is successfully fabricated for the first time, for photo-oxidation of RhB and photo-reduction of Cr(VI) to Cr(III). The resulting N0.1/Bi2O3/g-C3N4 (3%) nanocomposite showed an optimal Cr(VI) photo-reduction and RhB photo-oxidation rates under visible-light irradiation, being 3–4 times higher than that of pure α-Bi2O3. The results from XPS confirmed the substitution of nitrogen with various oxidation states from N3+ to Nx+ (x < 5), due to the existence of different nitrogen oxides including N−O, O−N=O, and NO3− in the crystal structure. We investigated the reaction mechanism using catalytic tests, impedance spectroscopy, EPR technique, and density functional calculations. The DFT calculations presented the appearance of a new mid-gap hybrid of p states, comprised of N 2p, O 2p, and Bi 6P states, which enhance light absorption capacity and narrow band gap. The theoretical results were in excellent agreement with experimental UV-Vis data. The N0.1/Bi2O3/g-C3N4 nanocomposite exhibited acceptable practical application value and recycling ability for removal of the contaminants. Such improved photocatalytic activity is originated from the modified band positions, new electron evolution pathway, introducing defects in α-Bi2O3 by insertion of N atoms into the Bi sites, and the enhanced charge carrier mobility between N0.1/Bi2O3 and g-C3N4. The strategy to form nitrogen-doped bismuth-based nanocomposites may open a new opportunity to design atomic-level electronic defects by feasible methods to obtain a versatile photocatalyst material with simultaneous photo-reduction and photo-oxidation ability for removal of Cr(VI) and organic dyes from water.

Keywords: catalysts; nanostructures; composites; semiconductors; bismuth; photochemistry; oxidation-reduction reaction; oxidation (active); water purification

Contributing organizations

Ministry reporting: Yes

Reporting Year: 2021

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