Synthesis of heterojunction photocatalysts composed of Ag 2 S quantum dots combined with Bi 4 Ti 3 O 12 nanosheets for the degradation of dyes

  • Xinxin Zhao
  • Hua YangEmail author
  • Ruishan Li
  • Ziming Cui
  • Xueqin Liu
Research Article


Facilitating the separation of photogenerated electron/hole pairs and widening the light-responsive region are crucial to enhance the overall photocatalytic performance of photocatalysts. To achieve this aim, here we have prepared Ag2S/Bi4Ti3O12 heterojunction composite photocatalysts by assembling Ag2S quantum dots onto the surface of Bi4Ti3O12 nanosheets. Transmission electron microscopy observation demonstrates that two types of Ag2S quantum dots separately with size of 40–70 and 7–17 nm are uniformly assembled onto the surface of large-sized Bi4Ti3O12 thin nanosheets. The as-prepared Ag2S/Bi4Ti3O12 heterojunction composites exhibit much enhanced light absorption (particularly in the visible and near-infrared region) and highly efficient separation of electrons and holes photogenerated in Bi4Ti3O12. Rhodamine B (RhB) aqueous solution was chosen as the target organic pollutant to evaluate the photocatalytic performance of the samples under simulated sunlight irradiation. It is found that the Ag2S/Bi4Ti3O12 heterojunction composites manifest significantly enhanced photocatalytic activity toward the RhB degradaton. In particular, the 15wt% Ag2S/Bi4Ti3O12 composite exhibits the highest photocatalytic activity, which is ca. 2.8 and 4.0 times higher than bare Bi4Ti3O12 and Ag2S, respectively. The enhanced photocatalytic activity of the composites can be explained as a result of the Z-scheme electron transfer from the conduction band of Bi4Ti3O12 to the valence band of Ag2S, and thus more photogenerated holes in the valence band of Bi4Ti3O12 and electrons in the conduction band of Ag2S are able to participate in the photocatalytic reactions. Active species trapping experiments were carried out, from which it is concluded that photogenerated holes and •O2 radicals play the dominant and secondary role in the photocatalysis, respectively.


Bi4Ti3O12 nanosheets Ag2S quantum dots Ag2S/Bi4Ti3O12 heterojunctions Photocatalytic degradation of rhodamine B Photocatalytic mechanism 


Funding information

This work was supported by the National Natural Science Foundation of China (Grant No. 51662027), HongLiu First-Class Disciplines Development Program of Lanzhou University of Technology and Chongqing Research Program of Basic Research and Frontier Technology (Grant No. cstc2015jcyjA50033).


  1. Abdel-Shafy HI, El-Khateeb MA, Mansour MSM (2016) Treatment of leather industrial wastewater via combined advanced oxidation and membrane filtration. Water Sci Technol 74:586–594CrossRefGoogle Scholar
  2. Bai LJ, Cai XT, Lu JJ, Li LN, Zhong SX, Wu L, Gong PJ, Chen JR, Bai S (2018) Surface and interface engineering in Ag2S@MoS2 core-shell nanowire heterojunctions for enhanced visible photocatalytic hydrogen production. ChemCatChem 10:2107–2114CrossRefGoogle Scholar
  3. Boruah PK, Sharma B, Karbhal I, Shelke MV, Das MR (2017) Ammonia-modified graphene sheets decorated with magnetic Fe3O4 nanoparticles for the photocatalytic and photo-Fenton degradation of phenolic compounds under sunlight irradiation. J Hazard Mater 325:90–100CrossRefGoogle Scholar
  4. Brown MA, De Vito SC (1993) Predicting azo dye toxicity. Crit Rev Environ Sci Technol 23:249–324CrossRefGoogle Scholar
  5. Cao TP, Li YJ, Wang CH, Zhang ZY, Zhang MY, Shao CL, Liu YC (2011) Bi4Ti3O12 nanosheets/TiO2 submicron fibers heterostructures: in situ fabrication and high visible light photocatalytic activity. J Mater Chem 21:6922–6927CrossRefGoogle Scholar
  6. Carp O, Huisman C, Reller A (2004) Photoinduced reactivity of titanium dioxide. Prog Solid State Chem 32:33–177CrossRefGoogle Scholar
  7. Chen Z, Jiang H, Jin W, Shi C (2016) Enhanced photocatalytic performance over Bi4Ti3O12 nanosheets with controllable size and exposed {001} facets for Rhodamine B degradation. Appl Catal B-Environ 180:698–706CrossRefGoogle Scholar
  8. Cui ZM, Yang H, Zhao XX (2018) Enhanced photocatalytic performance of g-C3N4/Bi4Ti3O12 heterojunction. Mater Sci Eng B 229:160–172CrossRefGoogle Scholar
  9. Cummins SE, Cross LE (1968) Electrical and optical properties of ferroelectric Bi4Ti3O12 single crystals. J Appl Phys 39:2268–2274CrossRefGoogle Scholar
  10. de Caprariis B, De Filippis P, Hernandez AD, Petrucci E, Petrullo A, Scarsella M (2017) Pyrolysis wastewater treatment by adsorption on biochars produced by poplar biomass. J Environ Manag 197:231–238CrossRefGoogle Scholar
  11. Di LJ, Yang H, Xian T, Chen XJ (2017) Enhanced photocatalytic activity of NaBH4 reduced BiFeO3 nanoparticles for rhodamine B decolorization. Materials 10:1118CrossRefGoogle Scholar
  12. Di LJ, Yang H, Xian T, Chen XJ (2018a) Facile synthesis and enhanced visible-light photocatalytic activity of novel p-Ag3PO4/n-BiFeO3 heterojunction composites for dye degradation. Nanoscale Res Lett 13:257CrossRefGoogle Scholar
  13. Di LJ, Yang H, Xian T, Chen XJ (2018b) Construction of Z-scheme g-C3N4/CNT/Bi2Fe4O9 composites with improved simulated-sunlight photocatalytic activity for the dye degradation. Micromachines 9:613Google Scholar
  14. Ding RQ, Dai H, Li MC, Jiang B, Mwenya T, Song DD, Geng C (2015) Special P-N junction photocatalytic NiO/Ag2S nanocomposite synthesized by hydrothermal method. Nanosci Nanotechnol Lett 7:387–391CrossRefGoogle Scholar
  15. Du C, Li DH, He QY, Liu JM, Li W, He GN, Wang YZ (2016) Design and simple synthesis of composite Bi12TiO20/Bi4Ti3O12 with a good photocatalytic quantum efficiency and high production of photo-generated hydroxyl radicals. Phys Chem Chem Phys 18:26530–26538CrossRefGoogle Scholar
  16. Dutta DP, Tyagi AK (2016) Facile sonochemical synthesis of Ag modified Bi4Ti3O12 nanoparticles with enhanced photocatalytic activity under visible light. Mater Res Bull 74:397–407CrossRefGoogle Scholar
  17. Foster HA, Ditta IB, Varghese S, Steele A (2011) Photocatalytic disinfection using titanium dioxide: spectrum and mechanism of antimicrobial activity. Appl Microbiol Biotechnol 90:1847–1868CrossRefGoogle Scholar
  18. Gan HH, Liu J, Zhang HN, Qian YX, Jin HX, Zhang KF (2018) Enhanced photocatalytic removal of hexavalent chromium and organic dye from aqueous solution by hybrid bismuth titanate Bi4Ti3O12/Bi2Ti2O. Res Chem Intermed 44:2123–2138CrossRefGoogle Scholar
  19. Gao XM, Dai Y, Zhang Y, Wang ZH, Fu F (2017) Preparation and photocatalytic performance of spherical-like Bi4Ti3O12 composite. Chinese J Inorg Chem 33:455–462Google Scholar
  20. He ZM, Xia YM, Tang B, Jiang XF, Su JB (2016a) Fabrication and photocatalytic property of ZnO/Cu2O core-shell nanocomposites. Mater Lett 184:148–151CrossRefGoogle Scholar
  21. He HB, Xue SS, Wu Z, Yu CL, Yang K, Peng GM, Zhou WQ, Li DH (2016b) Sonochemical fabrication, characterization and enhanced photocatalytic performance of Ag2S/Ag2WO4 composite microrods. Chin J Catal 37:1841–1850CrossRefGoogle Scholar
  22. Hou DF, Hu XL, Hu P, Zhang W, Zhang MF, Huang YH (2013) Bi4Ti3O12 nanofibers–BiOI nanosheets p–n junction: facile synthesis and enhanced visible-light photocatalytic activity. Nanoscale 5:9764–9772CrossRefGoogle Scholar
  23. Hu XL, Li YY, Tian J, Yang HR, Cui HZ (2017) Highly efficient full solar spectrum (UV-vis-NIR) photocatalytic performance of Ag2S quantum dot/TiO2 nanobelt heterostructures. J Ind Eng Chem 45:189–196CrossRefGoogle Scholar
  24. Huang YC, Long B, Li HB, Balogun MS, Rui ZB, Tong YX, Ji HB (2015) Enhancing the photocatalytic performance of BiOClxI1–x by introducing surface disorders and Bi nanoparticles as cocatalyst. Adv Mater Interfaces 2:1500249CrossRefGoogle Scholar
  25. Jiang W, Wu ZM, Yue XN, Yuan SJ, Lu HF, Liang B (2015) Photocatalytic performance of Ag2S under irradiation with visible and near-infrared light and its mechanism of degradation. RSC Adv 5:24064–24071CrossRefGoogle Scholar
  26. Konstantinou IK, Albanis TA (2004) TiO2-assisted photocatalytic degradation of azo dyes in aqueous solution: kinetic and mechanistic investigations: a review. Appl Catal B-Environ 49:1–14CrossRefGoogle Scholar
  27. Kumar S, Singh AP, Bera C, Thirumal M, Mehta BR, Ganguli AK (2016) Visible-light-driven photoelectrochemical and photocatalytic performance of NaNbO3/Ag2S core-shell heterostructures. ChemSusChem 9:1850–1858CrossRefGoogle Scholar
  28. Liu Y, Zhang MY, Li L, Zhang XT (2015) In situ ion exchange synthesis of the Bi4Ti3O12/Bi2S3 heterostructure with enhanced photocatalytic activity. Catal Commun 60:23–26CrossRefGoogle Scholar
  29. Liu YB, Zhu GQ, Gao JZ, Hojamberdiev M, Lu HB, Zhu RL, Wei XM, Liu P (2016a) A novel CeO2/Bi4Ti3O12 composite heterojunction structure with an enhanced photocatalytic activity for bisphenol A. J Alloys Compd 688:487–496CrossRefGoogle Scholar
  30. Liu YB, Zhu GQ, Gao JZ, Peng JH, Gao JZ, Wang CH, Liu P (2016b) One-step molten-salt method fabricated Bi2Ti2O7/Bi4Ti3O12 composites with enhanced photocatalytic activity. J Mater Sci Mater Electron 28:2172–2182CrossRefGoogle Scholar
  31. Ning XB, Ge SS, Wang XT, Li H, Li XR, Liu XQ, Huang YL (2018) Preparation and photocathodic protection property of Ag2S-TiO2 composites. Journal of Environmental Chemical Engineering 6:311–324CrossRefGoogle Scholar
  32. Panmand RP, Kumar G, Mahajan SM, Kulkarni MV, Amalnerkar DP, Kale BB, Gosavi SW (2011) Functionality of bismuth sulfide quantum dots/wires-glass nanocomposite as an optical current sensor with enhanced Verdet constant. J Appl Phys 109:033101CrossRefGoogle Scholar
  33. Qian K, Jiang ZF, Shi H, Wei W, Zhu CZ, Xie JM (2016) Constructing mesoporous Bi4Ti3O12 with enhanced visible light photocatalytic activity. Mater Lett 183:303–306CrossRefGoogle Scholar
  34. Reddy DA, Ma R, Choi MY, Kim TK (2015) Reduced graphene oxide wrapped ZnS–Ag2S ternary compositessynthesized via hydrothermal method: applications in photocatalystdegradation of organic pollutants. Appl Surf Sci 324:725–735CrossRefGoogle Scholar
  35. Sadollahkhani A, Kazeminezhad I, Nur O, Willander M (2015) Cation exchange assisted low temperature chemical synthesis of ZnO@Ag2S core-shell nanoparticles and their photo-catalytic properties. Mater Chem Phys 163:485–495CrossRefGoogle Scholar
  36. Shanker U, Rani M, Jassal V (2017) Degradation of hazardous organic dyes in water by nanomaterials. Environ Chem Lett 15:623–642CrossRefGoogle Scholar
  37. Shi BT, Yin HY, Gong JY, Nie QL (2017a) A novel p-n heterojunction of Ag2O/Bi4Ti3O12 nanosheet with exposed (001) facets for enhanced visible-light-driven photocatalytic activity. Mater Lett 201:74–77CrossRefGoogle Scholar
  38. Shi B, Yin H, Gong J, Nie Q (2017b) Ag/AgCl decorated Bi4Ti3O12 nanosheet with highly exposed (001) facets for enhanced photocatalytic degradation of Rhodamine B, Carbamazepine and Tetracycline. Appl Surf Sci 419:614–623CrossRefGoogle Scholar
  39. Sing KSW, Williams RT (2004) Physisorption hysteresis loops and the characterization of nanoporous materials. Adsorpt Sci Technol 22:773–782CrossRefGoogle Scholar
  40. Stoller MD, Park SJ, Zhu YW, An JH, Ruoff RS (2008) Graphene-based ultracapacitors. Nano Lett 8:3498–3502CrossRefGoogle Scholar
  41. Subash B, Krishnakumar B, Pandiyan V, Swaminathan M, Shanthi M (2012) An efficient nanostructured Ag2S–ZnO for degradation of Acid Black 1 dye under day light illumination. Sep Purif Technol 96:204–213CrossRefGoogle Scholar
  42. Tanaka K, Padermpole K, Hisanaga T (2000) Photocatalytic degradation of commercial azo dyes. Water Res 34:327–333CrossRefGoogle Scholar
  43. Tang RF, Su HF, Sun YW, Zhang XX, Li L, Liu CH, Wang BQ, Zeng SY, Sun DZ (2016) Facile fabrication of Bi2WO6/Ag2S heterostructure with enhanced visible-light-driven photocatalytic performances. Nanoscale Res Lett 11:126CrossRefGoogle Scholar
  44. Teoh WY, Scott JA, Amal R (2012) Progress in heterogeneous photocatalysis: from classical radical chemistry to engineering nanomaterials and solar reactors. J Phys Chem Lett 3:629–639CrossRefGoogle Scholar
  45. Thamima M, Andou Y, Karuppuchamy S (2017) Microwave assisted synthesis of perovskite structured BaTiO3 nanospheres via peroxo route for photocatalytic applications. Ceram Int 43:556–563CrossRefGoogle Scholar
  46. Tian J, Yan TJ, Qiao Z, Wang LL, Li WJ, You JM, Huang BB (2017) Anion-exchange synthesis of Ag2S/Ag3PO4 core/shell composites with enhanced visible and NIR light photocatalytic performance and the photocatalytic mechanisms. Appl Catal B-Environ 209:566–578CrossRefGoogle Scholar
  47. Vaiano V, Sacco O, Sannino D, Ciambelli P (2015) Nanostructured N-doped TiO2 coated on glass spheres for the photocatalytic removal of organic dyes under UV or visible light irradiation. Appl Catal B-Environ 170:153–161CrossRefGoogle Scholar
  48. Wang XF, Zhan S, Wang Y, Wang P, Yu HG, Yu JG, Hu CZ (2014a) Facile synthesis and enhanced visible-light photocatalytic activity of Ag2S nanocrystal-sensitized Ag8W4O16 nanorods. J Colloid Interface Sci 422:30–37CrossRefGoogle Scholar
  49. Wang HL, Zhang LS, Chen ZG, Hu JQ, Li SJ, Wang ZH, Liu JS, Wang XC (2014b) Semiconductor heterojunction photocatalysts: design, construction, and photocatalytic performances. Chem Soc Rev 43:5234–5244CrossRefGoogle Scholar
  50. Wang WG, Xu ZX, Li HZ, Jin W (2016) Optimization of coagulation-flocculation process for combined sewer overflow wastewater treatment using response surface methodology. Desalin Water Treat 57:14824–14832CrossRefGoogle Scholar
  51. Wang F, Yang H, Zhang YC (2018a) Enhanced photocatalytic performance of CuBi2O4 particles decorated with Ag nanowires. Mater Sci Semicond Process 73:58–66CrossRefGoogle Scholar
  52. Wang F, Yang H, Zhang HM, Jiang JL (2018b) Growth process and enhanced photocatalytic performance of CuBi2O4 hierarchical microcuboids decorated with AuAg alloy nanoparticles. J. Mater Sci-Mater El 29:1304–1316CrossRefGoogle Scholar
  53. Xia YM, He ZM, Hu KJ, Tang B, Su JB, Liu Y, Li XP (2018a) Fabrication of n-SrTiO3/p-Cu2O heterojunction composites with enhanced photocatalytic performance. J Alloys Compd 753:356–363CrossRefGoogle Scholar
  54. Xia YM, He ZM, Lu YL, Tang B, Sun SP, Su JB, Li XP (2018b) Fabrication and photocatalytic property of magnetic SrTiO3/NiFe2O4 heterojunction nanocomposites. RSC Adv 8:5441–5450CrossRefGoogle Scholar
  55. Yadav S, Jaiswar G (2017) Review on undoped/doped TiO2 nanomaterial; synthesis and photocatalytic and antimicrobial activity. J Chin Chem Soc 64:103–116CrossRefGoogle Scholar
  56. Yan YX, Yang H, Zhao XX, Li RS, Wang XX (2018a) Enhanced photocatalytic activity of surface disorder-engineered CaTiO3. Mater Res Bull 105:286–290CrossRefGoogle Scholar
  57. Yan YX, Yang H, Zhao XX, Zhang HM, Jiang JL (2018b) A hydrothermal route to the synthesis of CaTiO3 nanocuboids using P25 as the titanium source. J Electron Mater 47:3045–3050Google Scholar
  58. Ye YC, Yang H, Wang XX, Feng WJ (2018a) Photocatalytic, Fenton and photo-Fenton degradation of RhB over Z-scheme g-C3N4/LaFeO3 heterojunction photocatalysts. Mater Sci Semicond Process 82:14–24CrossRefGoogle Scholar
  59. Ye YC, Yang H, Zhang HM, Jiang JL (2018b) A promising Ag2CrO4/LaFeO3 heterojunction photocatalyst applied to photo-Fenton degradation of RhB. Environ Technol:1–18.
  60. Zhang YZ, Chen ZW, Lu ZY (2018) A facile method for the preparation of colored Bi4Ti3O12−x nanosheets with enhanced visible-light photocatalytic hydrogen evolution activity. Nanomaterials 8:261CrossRefGoogle Scholar
  61. Zhao W, Jia Z, Lei E, Wang LG, Li ZY, Dai YJ (2013) Photocatalytic degradation efficacy of Bi4Ti3O12 micro-scale platelets over methylene blue under visible light. J Phys Chem Solids 74:1604–1607CrossRefGoogle Scholar
  62. Zhao W, Wang HX, Feng XN, Jiang WY, Zhao D, Li JY (2015) Hydrothermal synthesis and photocatalytic activities of Bi4Ti3O12/SrTiO3 composite micro-platelets. Mater Res Bull 70:179–183CrossRefGoogle Scholar
  63. Zhao YW, Fan HQ, Fu K, Ma LT, Li MM, Fang JW (2016) Intrinsic electric field assisted polymeric graphitic carbon nitride coupled with Bi4Ti3O12/Bi2Ti2O7 heterostructure nanofibers toward enhanced photocatalytic hydrogen evolution. Int J Hydrogen Energ 41:16913–16926CrossRefGoogle Scholar
  64. Zhao X, Yang H, Cui Z, Li R, Feng W (2017) Enhanced photocatalytic performance of Ag-Bi4Ti3O12 nanocomposites prepared by a photocatalytic reduction method. Mater Technol 32:870–880CrossRefGoogle Scholar
  65. Zhao W, Dai BL, Zhu FX, Tu XY, Xu JM, Zhang LL, Li SY, Leung DYC, Sun C (2018a) A novel 3D plasmonic p-n heterojunction photocatalyst: Ag nanoparticles on flower-like p-Ag2S/n-BiVO4 and its excellent photocatalytic reduction and oxidation activities. Appl Catal B-Environ 229:171–180CrossRefGoogle Scholar
  66. Zhao XX, Yang H, Li SH, Cui ZM, Zhang CR (2018b) Synthesis and theoretical study of large-sized Bi4Ti3O12 square nanosheets with high photocatalytic activity. Mater Res Bull 107:180–188CrossRefGoogle Scholar
  67. Zheng CX, Yang H (2018) Assembly of Ag3PO4 nanoparticles on rose flower-like Bi2WO6 hierarchical architectures for achieving high photocatalytic performance. J Mater Sci-Mater Electron 29:9291–9300CrossRefGoogle Scholar
  68. Zheng CX, Yang H, Cui ZM, Zhang HM, Wang XX (2017) A novel Bi4Ti3O12/Ag3PO4 heterojunction photocatalyst with enhanced photocatalytic performance. Nanoscale Res Lett 12:608CrossRefGoogle Scholar
  69. Zou HM, Wang Y (2017) Azo dyes wastewater treatment and simultaneous electricity generation in a novel process of electrolysis cell combined with microbial fuel cell. Bioresour Technol 235:167–175CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Xinxin Zhao
    • 1
    • 2
  • Hua Yang
    • 1
    • 2
  • Ruishan Li
    • 2
  • Ziming Cui
    • 2
  • Xueqin Liu
    • 3
  1. 1.State Key Laboratory of Advanced Processing and Recycling of Non-ferrous MetalsLanzhou University of TechnologyLanzhouChina
  2. 2.School of ScienceLanzhou University of TechnologyLanzhouChina
  3. 3.School of ScienceChongqing University of TechnologyChongqingChina

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