Fabrication of full-spectrum response Bi2O4/BiO2−x heterojunction as high-performance photocatalyst for organic pollutants removal by a two-step hydrothermal method

• Published in: Journal of materials science 2022-01, Vol.57 (4), p.2467-2482
• Main Authors: Yang, Ruofan, Qin, Feng, Zheng, Shizheng, Hu, Changyuan, Ma, Yanting, Liang, Baiping, Bai, Yangyang, Zhang, Cuiqing
• Format: Article
• Language: English
• Subjects: Absorption; Bismuth; Catalytic activity; Characterization and Evaluation of Materials; Charge efficiency; Chemical Routes to Materials; Chemistry and Materials Science; Classical Mechanics; Crystallography and Scattering Methods; Current carriers; Deionization; Dyes; Heterojunctions; Heterostructures; hot water treatment; Hydrothermal reactions; intermediate product; irradiation; light; Materials Science; methyl orange; Near infrared radiation; phenol; Photocatalysis; Photocatalysts; Photodegradation; Pollutants; pollution control; Polymer Sciences; Solid Mechanics
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-021-06788-z

Though Bi 2 O 4 photocatalyst has attracted enormous concern because of its strong absorption in visible light region recently, the high recombination possibility of photoinduced electron–hole pairs and lack of the near-infrared light (NIR) harvesting capability for Bi 2 O 4 alone restrict its photocatalytic performance. Herein, Bi 2 O 4 /BiO 2− x junction was developed by a two-step hydrothermal method. A ternary BiO 2− x /NaBiO 3 ·2H 2 O/NaBiO 3 · x H 2 O or binary BiO 2− x /NaBiO 3 · x H 2 O intermediate product was formed firstly during the first hydrothermal reaction depending on the concentration of NaOH solution. Then, Bi 2 O 4 /BiO 2− x heterostructure was produced when the ternary and binary intermediate product underwent the second hydrothermal process in deionized water. The content of BiO 2− x in the Bi 2 O 4 /BiO 2− x heterojunction could be easily tuned by changing the NaOH concentration in the first-step hydrothermal reaction. Bi 2 O 4 /BiO 2− x heterojunction could not only raise the charge carriers’ separation efficiency but also broaden the optical absorption range to NIR area. As a result, the optimal Bi 2 O 4 /BiO 2− x sample exhibits improved visible light photocatalytic degradation activity toward methyl orange (MO) and phenol, which is 2.67-fold and 2.84-fold higher than pristine Bi 2 O 4 and BiO 2− x , respectively. Under NIR irradiation, the optimal Bi 2 O 4 /BiO 2− x sample also reveals superior catalytic activity for the degradation of MO, which is 11.99 times as high as that of single Bi 2 O 4 . The role of NaOH in the first-step hydrothermal reaction is discussed. The probable photocatalytic mechanism of Bi 2 O 4 /BiO 2− x junction is put forward as well. This work supplies a novel strategy for designing full-spectrum response bismuth-based oxide heterojunction with high photocatalytic performance for organic pollutant removal. Graphical abstract