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A nanocrystalline oxygen-deficient bismuth oxide as an efficient adsorbent for effective visible-light-driven photocatalytic performance toward organic pollutant degradation
- Lv, Ying, Xu, Zhanglian, Nakane, Koji, Kobayashi, Hisayoshi
- Journal of colloid and interface science 2018 v.531 pp. 463-472
- adsorbents, adsorption, bismuth, crystal structure, density functional theory, irradiation, methyl orange, methylene blue, nanocrystals, oxidation, phenol, photocatalysis, pollutants, rhodamines, semiconductors
- In this work, a simple binary oxygen-deficient Bi2O4−x oxide was prepared, and its crystal structure, optical property, band structure and electronic structure were systematically investigated. Plane-wave-based density functional theory (DFT) calculations were also carried out to determine that Bi2O4−x is a typical indirect-gap semiconductor with the bandgap of 1.1 eV. Bi2O4−x adsorbed ca. 99% of rhodamine B and methyl orange, ca. 95% of methylene blue and ca. 80% of phenol in the dark within initial 30 min. The interaction of the oxygen-deficient structure-induced hydroxyls with pollutant molecules is responsible for the excellent adsorption capacity. Due to its excellent adsorption capacity, Bi2O4−x showed much higher photocatalytic degradation activity toward these pollutants (except for methylene blue) under visible light irradiation than the well-studied Bi2O4, Bi2O3 and P25, which had poor or negligible adsorption capacity toward the pollutants. Methylene blue was degraded by Bi2O4−x with further Pd loading. The photocatalytic mechanism of the oxygen-deficient Bi2O4−x were explored. The scavenging test results showed that direct h+ oxidation contributes to the high photocatalytic activity of the oxygen-deficient Bi2O4−x. This study highlights the potential of developing Bi2O4−x-based materials as a new class with both excellent adsorption capacity and highly efficient photocatalytic activity toward versatile pollutants.