Efficient ytterbium-doped Bi2WO6 photocatalysts: Synthesis, the formation of oxygen vacancies and boosted superoxide yield for enhanced visible-light photocatalytic activity

• Published in: Journal of alloys and compounds Vol. 851; p. 156935
• Main Authors: Li, Xinyang, Li, Wenjun, Gu, Shaonan, Liu, Xintong, Li, Hongda, Ren, Chaojun, Ma, Xiaohui, Zhou, Hualei
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15-01-2021; Elsevier BV
• Subjects: Bismuth compounds; Catalytic activity; Crystal structure; Electron paramagnetic resonance; Holes (electron deficiencies); Hydrothermal crystal growth; Lattice vacancies; Light irradiation; Morphology; Nanomaterials; Optical properties; Oxygen; Oxygen vacancies; Performance degradation; Photocatalysis; Photocatalysts; Photocatalytic; Photoelectric effect; Photoelectric emission; Photoluminescence; Spectrum analysis; Superoxide anion radicals; Tungstates; X ray photoelectron spectroscopy; Yb–Bi2WO6; Ytterbium; Photocatalytic; Oxygen vacancies; Superoxide anion radicals; Yb–Bi2WO6
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.156935

Yb-doped Bi2WO6 nanomaterials were successfully synthesized using a mild hydrothermal method. Remarkably, Yb-doped Bi2WO6 photocatalysts exhibited a higher photocatalytic activity than pristine Bi2WO6 by degrading RhB under visible light irradiation. The optimum mass ratio of Yb to Bi2WO6 was 2.0%, and it presented the highest photo-degradation efficiency. The crystal structures, morphologies, surface chemical states, and optical properties of the as-synthesized photocatalysts were carried out by XRD, SEM, XPS and DRS, respectively. The results of electron paramagnetic resonance spectroscopy, radical trapping experiments, photoluminescence spectroscopy and photocurrent measurements indicated that the Yb-doped Bi2WO6 samples produced more oxygen vacancies and superoxide anion active groups (.O2−), inhibited the recombination of the photo-generated electron-hole pairs, and enhanced the photo-degradation performance. As a result, the dopant Yb3+ could enhance photocatalytic performance of Bi2WO6 by introducing oxygen vacancies into its lattice. This study provides a useful strategy for developing effective visible light photocatalysts.
Under visible light irradiation, the mechanism of the enhancement photocatalytic performance of Yb–Bi2WO6 samples was proposed, which effected on forming the oxygen vacancies, enhancing the production of superoxide anion active radicals, inhibiting the recombination of photo-generated charge carriers. [Display omitted]
•Doping of ytterbium could obviously improve the photocatalytic performance of Bi2WO6.•The optimum mass ratio of Yb to Bi2WO6 was 2.0%, and it presented the highest photo-degradation efficiency.•Doping of Yb3+ could form the oxygen vacancies and the formed oxygen vacancies make for produced more .O2−.•The possible degradation mechanism of Yb–Bi2WO6 photocatalysts was systematically discussed.•Provide a strategy to develop effective visible light catalysts.