Preparation and Properties of CdS/Spherical g-C₃N₄ n-n Heterojunction as a Visible-Light-Driven Photocatalyst for Tetracycline Degradation

Abstract

The CdS/ spherical g-C₃N₄ n-n heterojunction photocatalyst was fabricated via a solvothermal method. The tetracycline was used to characterize the photocatalytic properties of the as-developed hybrids. The photocatalytic degradation mechanism of the as-developed heterojunction photocatalyst was also analyzed. Research results show that CdS nanoparticles are well dispersed in the surface layer of spherical g-C₃N₄. Moreover, the mass ratio of CdS to spherical g-C₃N₄ will influence the photocatalytic activity of the asdeveloped composites, which shows the trend of first increasing and then decreasing as it increased. When the mass ratio is 7:1, in 25 min, the as-developed heterojunction shows 93.2 % of the maximum photocatalytic efficiency and still exhibits 83.6 % after 5 times cycle testing. Moreover, the as-developed hybrids can accelerate the electron transport and improve the separation efficiency of photo-generated carriers compared with pure samples. In addition, the holes and superoxide radicals are dominating active species during the photocatalytic degradation process.

Keywords

spherical g-C₃N₄ / photocatalysis / heterojunction / tetracycline

References

[1] Chen D, Liu Z F, Zhou M, et al. Enhanced Photoelectrochemical Water Splitting Performance of α-Fe₂O₃ Nanostructures Modified with Sb₂S₃ and Cobalt Phosphate[J]. J. Alloy. Compd., 2018, 742: 918-927.

[2] Liu Z F, Zhang J, Yan W G. Enhanced Photoelectrochemical Water Splitting of Photoelectrode Simultaneous Decorated with Cocatalysts Based on Spatial Charge Separation and Transfer[J]. ACS Sustain. Chem. Eng., 2018, 6(3): 3565-3574.

[3] Wang W, Fang J J, Shao S F, et al. Compact and Uniform TiO₂@g-C₃N₄, Core-Shell Quantum Heterojunction for Photocatalytic Degradation of Tetracycline Antibiotics[J]. Appl. Catal. B-Environ., 2017, 217: 57-64.

[4] Martins A C, Cazetta A L, Pezoti O, et al. Sol-Gel Synthesis of New TiO₂/Activated Carbon Photocatalyst and Its Application for Degradation of Tetracycline[J]. Ceram. Int., 2017, 43(5): 4411-4418.

[5] Santhosh C, Velmurugan V, Jacob G, et al. Role of Nanomaterials in Water Treatment Applications: A Review[J]. Chem. Eng. J., 2016, 306: 1116-1137.

[6] Jiang H L, Li X Q, Tian L, et al. Defluoridation Investigation of Yttrium by Laminated Y-Zr-Al Tri-metal Nanocomposite and Analysis of the Fluoride Sorption Mechanism[J]. Sci. Total Environ., 2019, 648: 1342-1353.

[7] Tian L, Jiang H L, Chen P H, et al. A Novel GO/PNIPAm Hybrid with Two Functional Domains Can Simultaneously Effectively Adsorb and Recover Valuable Organic and Inorganic Resources[J]. Chem. Eng. J., 2018, 343: 607-618.

[8] Wu X F, Li H, Sun Y, et al. One-Step Hydrothermal Synthesis of In_2.77S₄ Nanosheets with Efficient Photocatalytic Activity under Visible Light[J]. Appl. Phys. A-Mater., 2017, 123(11): 709

[9] Zhou M, Liu Z H, Song Q G, et al. Hybrid 0D/2D Edamame Shaped ZnIn₂S₄ Photoanode Modified by Co-Pi and Pt for Charge Management Towards Efficient Photoelectrochem Water Splitting[J]. Appl. Catal. B-Environ., 2019, 244: 188-196.

[10] Wu X F, Li H, Sun Y, et al. Synthesis of SnS₂/Few Layer Boron Nitride Nanosheets Composites As a Novel Material for Visible-Light-Driven Photocatalysis[J]. Appl. Phys. A-Mater., 2017, 19(6): 193

[11] Jiang H L, Li M L, Liu J, et al. Alkali-Free Synthesis of a Novel Heterostructured CeO₂-TiO₂ Nanocomposite with High Performance to Reduce Cr(VI) under Visible Light[J]. Ceram. Int., 2018, 44: 2709-2717.

[12] Sharma S, Umar A, Mehta S K, et al. Solar Light Driven Photocatalytic Degradation of Levofloxacin Using TiO₂/Carbon-Dots Nanocomposite[J]. New J. Chem., 2018, 42: 7445-7456.

[13] Lan Y Y, Liu Z F, Guo Z G, et al. ZnO/ZnFe₂O₄ Uniform Core-Shell Heterojunction With Tubular Structure Modified by NiOOH for Efficient Photoelectrochemical Water Splitting[J]. Dalton T., 2018, 47: 12181-12187.

[14] Ma C H, Liu Z F, Cai Q J, et al. ZnO Photoelectrode Simultaneous Modified with Cu₂O and Co-Pi Based on Broaden Light Absorption and Efficient Photogenerated Carriers Separation[J]. Inorg. Chem. Front., 2018, 5: 2571-2578.

[15] Zhao J H, Nan J, Zhao Z W, et al. Energy-Efficient Fabrication of a Novel Multivalence Mn₃O₄-MnO₂ Heterojunction for Dye Degradation under Visible Light Irradiation[J]. Appl. Catal. B-Environ., 2017, 202: 509-517.

[16] Wang Y J, Zu X H, Yi G B, et al. Gap-Plasmon of Fe₃O₄@Ag Core-Shell Nanostructures for Highly Enhanced Fluorescence Detection of Rhodamine B[J]. J. Wuhan Univ. Technol.-Mater. Sci. Ed., 2017, 32(2): 264-271.

[17] Yang M, Jin X Q. Visible Light-Induced Cr-Doped SrTiO₃-g-C₃N₄ Composite for Improved Photocatalytic Performance[J]. J. Wuhan Univ. Technol.-Mater. Sci. Ed., 2014, 29(6): 1111-1116.

[18] Xu H Y, Wu L C, Jin L G, et al. Combination Mechanism and Enhanced Visible-Light Photocatalytic Activity and Stability of CdS/g-C₃N₄ Heterojunctions[J]. J. Mater. Sci. Technol., 2017, 33: 32-40.

[19] Wang Z Y, Guan W, Sun Y J, et al. Water-Assisted Production of Honeycomb-Like g-C₃N₄ with Ultralong Carrier Lifetime and Outstanding Photocatalytic Activity[J]. Nanoscale, 2015, 7: 2471-2479.

[20] Fan M S, Song C J, Chen T J, et al. Visible-Light-Drived High Photocatalytic Activities of Cu/g-C₃N₄ Photocatalysts for Hydrogen Production[J]. RSC Adv., 2016, 6: 34633-34640.

[21] Chen D, Liu Z F. Dual-Axial Gradient Doping (Zr and Sn) on Hematite for Promoting Charge Separation in Photoelectrochemical Water Splitting[J]. Chemsuschem, 2018, 11: 3438-3448.

[22] Panneri S, Ganguly P, Mohan M, et al. Photoregenerable, Bifunctional Granules of Carbon-Doped g-C₃N₄ as Adsorptive Photocatalyst for the Efficient Removal of Tetracycline Antibiotic[J]. ACS Sustain. Chem. Eng., 2017, 5(2): 1610-1618.

[23] Zheng N G, Ouyang T, Chen Y B, et al. Ultrathin CdS Shell-Sensitized Hollow S-Doped CeO₂ Spheres for Efficient Visible-Light Photocatalysis[J]. Catal. Sci. Technol., 2019, 9: 1357-1364.

[24] Mao Z Y, Chen J J, Yang Y F, et al. Novel g-C₃N₄/CoO Nanocomposites with Significantly Enhanced Visible-Light Photocatalytic Activity for H₂ Evolution[J]. ACS Appl. Mater. Inter., 2017, 9(14): 12427-12435.

[25] Ouyang T, Ye Y Q, Wu C Y, et al. Heterostructures Comprised of Co/β-Mo₂C-Encapsulated N-Doped Carbon Nanotubes as Bifunctional Electrodes for Water Splitting[J]. Angew. Chem. Int. Ed., 2019, 58: 4923-4928.

[26] Akple M S, Low J X, Wageh S, et al. Enhanced Visible Light Photocatalytic H₂-Production of g-C₃N₄/WS₂ Composite Heterostructures[J]. Appl. Surf. Sci., 2015, 358: 196-203.

[27] Zhao L H, Zhang L H, Lin H J, et al. Fabrication and Characterization of Hollow CdMoO₄ Coupled g-C₃N₄ Heterojunction with Enhanced Photocatalytic Activity[J]. J. Hazard. Mater., 2015, 299: 333-342.

[28] Li D, Shi F F, Jiang D L, et al. CdIn₂S₄/g-C₃N₄ Heterojunction Photocatalysts: Enhanced Photocatalytic Performance and Charge Transfer Mechanism[J]. RSC Adv., 2017, 7: 231-237.

[29] Fang Z L, Rong H F, Ya Z L, et al. In-Situ Synthesis of CdS/g-C₃N₄ Hybrid Nanocomposites with Enhanced Visible Photocatalytic Activity[J]. J. Mater. Sci., 2015, 50(8): 3057-3064.

[30] Wei R B, Huang Z L, Gu G H, et al. Dual-Cocatalysts Decorated Rimous CdS Spheres Advancing Highly-Efficient Visible-Light Photocatalytic Hydrogen Production[J]. Appl. Catal. B-Environ., 2018, 231: 101-107.

[31] Wang K, Li Y, Zhang G K, et al. 0D Bi Nanodots/2D Bi3NbO7 Nanosheets Heterojunctions for Efficient Visible Light Photocatalytic Degradation of Antibiotics: Enhanced Molecular Oxygen Activation and Mechanism Insight[J]. Appl. Catal. B-Environ., 2018, 240: 39-49.

[32] Xiao P, Jiang D L, Ju L X, et al. Construction of RGO/CdIn₂S₄/g-C₃N₄ Ternary Hybrid with Enhanced Photocatalytic Activity for the Degradation of Tetracycline Hydrochloride[J]. Appl. Surf. Sci., 2018, 433: 388-397.

[33] Wu X F, Zhao Z H, Sun Y, et al. Preparation and Characterization of Ag2CrO₄/Few Layer Boron Nitride Hybrids for Visible-Light-Driven Photocatalysis[J]. J. Nanopart. Res., 2017, 19(6): 193

[34] Zhang Z Y, Jiang D L, He M Q, et al. Construction of SnNb₂O₆ Nanosheet/g-C₃N₄ Nanosheet Two-Dimensional Heterostructures with Improved Photocatalytic Activity: Synergistic Effect and Mechanism Insight[J]. Appl. Catal. B-Environ., 2016, 183: 113-123.

[35] Wu X F, Li H, Su J Z, et al. Full Spectrum Responsive In2.77S₄/WS₂ P-N Heterojunction as an Efficient Photocatalyst for Cr(VI) Reduction and Tetracycline Oxidation[J]. Appl. Surf. Sci., 2019, 473: 992-1001.

[36] Xiao T T, Tang Z, Yang Y, et al. In Situ Construction of Hierarchical WO₃/g-C₃N₄ Composite Hollow Microspheres as a Z-Scheme Photocatalyst for the Degradation of Antibiotics[J]. Appl. Catal. B-Environ., 2017, 220: 417-428.

[37] Wu X F, Sun Y, Li H, et al. In-Situ Synthesis of Novel P-N Heterojunction of Ag₂CrO₄-Bi₂Sn₂O₇ Hybrids for Visible-Light-Driven Photocatalysis[J]. J. Alloy. Compd., 2018, 740: 1197-1203.

[38] Zhang J Y, Wang Y H, Jin J, et al. Efficient Visible-Light Photocatalytic Hydrogen Evolution and Enhanced Photostability of Core/Shell CdS/g-C₃N₄ Nanowires[J]. ACS Appl. Mater. Inter., 2013, 5(20): 10317-10324.

[39] Huang L Y, Xu H, Zhang R X, et al. Synthesis and Characterization of g-C₃N₄/MoO₃ Photocatalyst with Improved Visible-Light Photoactivity[J]. Appl. Surf. Sci., 2013, 283: 25-32.

[40] Wang J, Zhang G K, Li J, et al. Novel 3D Flower-Like BiOBr/Bi₂SiO₅ P-N Heterostructured Nanocomposite for Degradation of Tetracycline: Enhanced Visible Light Photocatalytic Activity and Mechanism[J]. ACS Sustain. Chem. Eng., 2018, 6: 14221-14229.