Fig 1

(a) Procedure illustration for the synthesis of BVO/WO3−x-10 composites. (b) XRD patterns and (c) FT-IR spectra of BiVO4, WO3−x, BVO/WO3−x-5, BVO/WO3−x-10, and BVO/WO3−x-15."

Fig 2

TEM images of (a) BVO/WO3−x-10 composite, (b) pure BiVO4, (c–d) HRTEM image of BVO/WO3−x-10. (e) SEM image of BVO/WO3−x-10. (f–i) EDS mapping images of Bi, V, O, and W elements."

Fig 3

XPS spectra of WO3 and WO3−x: (a) O 1s, (b) W 4f. XPS analysis of the WO3−x, BiVO4, and BVO/WO3−x-10: (c) Bi 4f, (d) V 2p, (e) O 1s, and (f) W 4f."

Fig 4

Photocatalytic degradation efficiencies of (a) TC and (c) Cr(Ⅵ). Kinetic curves for (b) the degradation of TC and (d) the reduction of Cr(Ⅵ) using different photocatalysts. Conditions for (a): [TC] = 10 mg·L−1, [Catalyst] = 0.05 g, [pH] = 7, [temperature] = 25 ℃, [beaker capacity] = 200 mL. Conditions for (c): [Cr(Ⅵ)] = 5 mg·L−1, [Catalyst] = 0.03 g, [pH] = 7, [temperature] = 25 ℃, [beaker capacity] = 200 mL."

Fig 5

Comparison of (a) TC degradation efficiencies and (b) kinetic curves under TC and Cr(Ⅵ) coexistence environment and in a single TC degradation system over BVO/WO3−x-10. Comparison of (c) Cr(Ⅵ) reduction efficiencies and (d) kinetic curves under TC and Cr(Ⅵ) coexistence environment and in a single Cr(Ⅵ) reduction system over BVO/WO3−x-10. Successive removal cycles of (e) TC and (f) Cr(Ⅵ) with BVO/WO3−x-10 composite. Conditions: [TC] = 10 mg·L−1, [Cr(Ⅵ)] = 5 mg·L−1, [Catalyst] = 0.03 g, [pH] = 7, [temperature] = 25 ℃, [beaker capacity] = 200 mL."

Fig 6

(a) Possible photocatalytic degradation pathway of TC by the BVO/WO3−x-10. Toxicity assessment of TC and its intermediate substance: (b, c) acute toxicity, (d) developmental toxicity, and (e) mutagenicity. (f) Cultivate mung beans in tap water, the Cr(Ⅵ)/TC coexistence solution, and the Cr(Ⅵ)/TC coexistence solution degraded by BVO/WO3−x-10 photocatalysts."

Fig 7

IR camera images of (a) as-prepared samples and (b) reaction solution. (c) Temperature mapping images under visible-light illumination during the real reaction process of photocatalytic TC for blank, BiVO4, and BVO/WO3−x-10 composite."

Fig 8

(a) PL spectra and (b) Photocurrent response density of WO3−x, BiVO4, and BVO/WO3−x-10. (c) Effect of different radical scavengers during TC degradation with BVO/WO3−x-10."

Fig 9

In situ XPS of (a) Bi 4f, (b) V 2p, (c) O 1s, and (d) W 4f under light irradiation."

Fig 10

Work function of (a) BiVO4, (b) WO3−x, and (c) WO3. (d) UV-vis DRS spectra of all the samples. (e) Kubelka-Munk function transformation and (f) valence band XPS profile of pure BiVO4, WO3, and WO3−x. (g–i) Fermi level modulation of WO3−x for intensified IEF of BVO/WO3−x−10 heterojunction."

Fig 11

Schematic diagram of possible carrier transfer mechanism of BVO/WO3−x under visible light irradiation."