Preparation of Bi₂O₃/BiOI Step-scheme Heterojunction Photocatalysts and Their Degradation Mechanism of Methylene Blue

Abstract

Bi₂O₃/BiOI step-scheme(S-scheme) heterojunction photocatalyst was synthesized by green calcination method, its degradation ability of methylene blue was investigated, and the photocatalytic performance of the Bi₂O₃/BiOI heterojunction, Bi₂O₃ and BiOI was compared. The structure and morphology of the samples were characterized by X- ray diffraction(XRD), field emission scanning electron microscopy (FESEM), and UV-vis diffuse reflection spectrum (UV-vis DRS). The degradation rate of methylene blue was analysised by spectrophotometry, and the calculation result showed that the degradation rate of methylene blue was 97.8% in 150 minutes. The first order kinetic rate constant of 10%Bi₂O₃/BiOI is 0.021 8 min⁻¹, which are 2.37 and 2.68 times of BiOI(0.009 18 min⁻¹) and Bi₂O₃ (0.008 03 min⁻¹) respectively. The calculation result shows that the work function of Bi₂O₃ and BiOI are 3.0 eV and 6.0 eV, respectively, by density functional theory(DFT). When this S-scheme heterojunction is used as a photocatalyst, the weaker electrons in the conduction band of BiOI will be combined with the weaker holes in the Bi₂O₃ valence band under combined effect with built-in electric field and band bending, which will retain stronger photoelectrons and holes between Bi₂O₃ and BiOI. This may be the internal reason for the efficient degradation of tetracycline by Bi₂O₃/BiOI S-scheme heterostructures.

Keywords

step-scheme heterojunction / methylene blue / antibiotic wastewater treatment / photocatalytic degradation / charge separation

References

[1] Alshaikh H, Al-Hajji L A, Mahmoud M H, et al. Visible-Light-Driven S-scheme Mesoporous Ag₃VO₄/C₃N₄ Heterojunction with Promoted Photocatalytic Performances[J]. Sep. Purif. Technol., 2021, 272: 118 914.

[2] Liu Q Q, He X D, Peng J J, et al. Hot-Electron-Assisted S-Scheme Heterojunction of Tungsten Oxide/Graphitic Carbon Nitride for Broad-Spectrum Photocatalytic H₂ Generation[J]. Chinese J. Catal., 2021, 42: 1 478-1 487.

[3] Zhang T, Maihemllti M, Okitsu K J, et al. In Situ. Appl. Surf. Sci., 2021, 556: 149 828.

[4] Enesca A, Isac L. Tuned S-Scheme Cu₂S-TiO₂-WO₃ Heterostructure Photocatalyst Toward S-Metolachlor (S-MCh) Herbicide Removal[J]. Materials, 2021, 14: 2 231.

[5] Kamali M, Sheibani S, Ataie A. Magnetic MgFe₂O₄- CaFe₂O₄ S-Scheme Photocatalyst Prepared from Recycling of Electric Arc Furnace Dust[J]. J. Environ. Manage., 2021, 290: 112 609.

[6] Zhang K, Li D Q, Tian Q Y, et al. Recyclable 0D/2D ZnFe2O4/Bi5Fe-Ti₃O₁₅ S-Scheme Heterojunction with Bismuth Decoration for Enhanced Visible-Light-Driven Tetracycline Photodegradation[J]. Ceram. Int., 2021, 47: 17 109-17 119.

[7] Yousefi S R, Ghanbari M, Amiri O, et al. Dy₂BaCuO₅/Ba₄DyCu₃O_9.09 S-Scheme Heterojunction Nanocomposite with Enhanced Photocatalytic and Antibacterial Activities[J]. J. Am. Ceram. Soc., 2021, 104: 2 952-2 965.

[8] Li J K, Li M, Jin Z L. Rational Design of a Cobalt Sulfide/Bismuth Sulfide S-Scheme Heterojunction for Efficient Photocatalytic Hydrogen Evolution[J]. J. Colloid. Interf. Sci, 2021, 592: 237-248.

[9] Liu Y, Hao X Q, Hu H Q, et al. High Efficiency Electron Transfer Realized over NiS₂/MoSe₂ S-Scheme Heterojunction in Photocatalytic Hydrogen Evolution[J]. Acta. Phys. -Chim. Sin., 2021, 37(6): 2 008 030

[10] Wang J, Wang G H, Cheng B, et al. Sulfur-Doped g-C₃N₄/TiO₂ S-Scheme Heterojunction Photocatalyst for Congo Red Photodegradation[J]. Chinese J. Catal., 2021, 42: 56-68.

[11] Landge V K, Sonawane S H, Sivakumar M, et al. S-Scheme Heterojunction Bi₂O₃-ZnO/Bentonite Clay Composite with Enhanced Photocatalytic Performance[J]. Sustain. Energy Techn., 2021, 45: 101 194.

[12] Liu X Y, Li J. S-Scheme Heterojunction ZnO/g-C₃N₄ Shielding Polyester Fiber Composites for the Degradation of MB[J]. Semicond. Sci. Tech., 2021, 36: 045 025.

[13] Gogoi D, Makkar P, Ghosh N N. Solar Light-Irradiated Photocatalytic Degradation of Model Dyes and Industrial Dyes by a Magnetic CoFe₂O₄- gC₃N₄ S-Scheme Heterojunction Photocatalyst[J]. ACS Omega, 2021, 6: 4 831-4 841.

[14] Zhang B, Hu X Y, Liu E Z, et al. Novel S — scheme 2D/2D BiOBr/g-C₃N₄ Heterojunctions with Enhanced Photocatalytic Activity[J]. Chinese J. Catal., 2021, 42: 1 519-1 529.

[15] Tan H Y, Zhang S L, Wu D Y, et al. Preparation of BiOI/BiOBr Heterojunction Catalyst and Its Photocatalytic Degradation of Rhodamine B[J]. Journal of Huanzhong Agricultural University, 2021, 40(3): 187-194.

[16] Chen X, Ke X C, Zhang J F, et al. Insight into the Synergy of Amine-Modified S-Scheme Cd_0.5Zn_0.5Se/porous g-C₃N₄ and Noble-Metal- Free Ni₂P for Boosting Photocatalytic Hydrogen Generation[J]. Ceram. Int., 2021, 47: 13 488-13 499.

[17] Chen X, Hu T P, Zhang J F, et al. Diethylenetriamine Synergistic Boosting Photocatalytic Performance with Porous g-C₃N₄/CdS — Diethylenetriamine 2D/2D S-Scheme Heterojunction[J]. J. Alloy Compd., 2021, 863: 158 068.

[18] Duan F, Ma Y, Lv P, et al. Oxygen Vacancy-Enriched Bi₂O₃/BiFeO₃ p-n Heterojunction Nanofibers with Highly Efficient Photocatalytic Activity Under Visible Light Irradiation[J]. Appl. Surf. Sci., 2021, 562: 150 171.

[19] Zhang H L, Li M, Wang W, et al. Designing 3D Porous BiOI/Ti₃C₂ Nanocomposite as a Superior Coating Photocatalyst for Photodegradation RhB and Photoreduction Cr (VI)[J]. Sep. Purif. Technol, 2021, 272: 118 911.

[20] Cao Y, Wang G R, Liu H, et al. Regular Octahedron Cu-MOFs Modifies Mn_0.05Cd_0.95S Nanoparticles to Form a S-Scheme Heterojunction for Photocatalytic Hydrogen Evolution[J]. Int. J. Hydrogen. Energ., 2021, 46: 7 230-7 240.

[21] Li J K, Li M, Jin Z L. 0D Cd_xZn_1−xS and Amorphous Co₉S₈ Formed S-Scheme Heterojunction Boosting Photocatalytic Hydrogen Evolution[J]. Mol. Catal., 2021, 501: 111 378.