Different core–shell structured silica–titania (SiO₂–TiO₂) nanocomposites were successfully synthesised in two successive stages. In the first stage, the core was synthesised by preparing poly[oligo(ethylene glycol)monomethyl ether methacrylate] (POEOMA) on the modified surface of silica nanoparticles (SiO₂–POEOMA). In the second stage, the shell was formed by depositing or coating tetrabutyl titanate (TBT) with SiO₂-polymer to obtain cauliflower-like, cauliflower–pomegranate-like and pomegranate-like SiO₂–POEOMA–TiO₂ microspheres; the weight ratio of added SiO₂–POEOMA to TBT (1:0.146, 0.293 and 0.439) was then adjusted. Later, the polymer layer was removed to obtain the cauliflower-like, cauliflower–pomegranate-like and pomegranate-like core–shell structured SiO₂–TiO₂ microspheres (CMs, CPMs and PMs). X-ray diffraction results showed that the TiO₂ shell was a pure anatase phase. SiO₂–TiO₂ microspheres were also characterised by N₂ adsorption–desorption; the results showed that a pore structure was found in the porous shell. Extensive porosity was generated in the shell because POEOMA was used as a template and pore-forming agent; the structure of CMs, CPMs and PMs remained almost unchanged. These results also showed that pore volumes and specific surface areas of the final products derived from N₂ sorption decreased as the content of TBT increased. PMs with the highest content of TiO₂ showed the most efficient photocatalytic activity.

References

1. 1)
  - 29. Sun, Z., Bai, C., Zheng, S., Yang, X., Frost, R.L.: ‘A comparative study of different porous amorphous silica minerals supported TiO2 catalysts’, Appl. Catal. A, Gen, 2013, 458, pp. 103–110 (doi: 10.1016/j.apcata.2013.03.035).
2. 2)
  - 28. Cheng, G., Wang, Z.G., Liu, Y.L., Zhang, J.L., Sun, D.H., Ni, J.Z.: ‘Magnetic affinity microspheres with meso-/macroporous shells for selective enrichment and fast separation of phosphorylated biomolecules’, ACS Appl. Mater. Interfaces, 2013, 5, (8), pp. 3182–3190 (doi: 10.1021/am400191u).
3. 3)
  - 6. Li, W., Deng, Y., Wu, Z., et al: ‘Hydrothermal etching assisted crystallization: a facile route to functional yolk-shell titanate microspheres with ultrathin nanosheets-assembled double shells’, J. Am. Chem. Soc., 2011, 133, pp. 15830–15833 (doi: 10.1021/ja2055287).
4. 4)
  - X. Chen , S.S. Mao . Titanium dioxide nanomaterials: synthesis, properties, modifications, and applications. Chem. Rev. , 2891 - 2959
5. 5)
  - 14. Ren, Y., Chen, M., Zhang, Y., Wu, L.: ‘Fabrication of rattle-type TiO2/SiO2 core/shell particles with both high photoactivity and UV-shielding property’, Langmuir, 2010, 26, (13), pp. 11391–11396 (doi: 10.1021/la1008413).
6. 6)
  - 26. Yin, J., Zhou, J.C.: ‘Novel polyethersulfone hybrid ultrafiltration membrane prepared with SiO2-g-(PDMAEMA-co-PDMAPS) and its antifouling performances in oil-in-water emulsion application’, Desalination, 2015, 365, pp. 46–56 (doi: 10.1016/j.desal.2015.02.017).
7. 7)
  - X.B. Chen , S.H. Shen , L.J. Guo , S.S. Mao . Semiconductor-based photocatalytic hydrogen generation. Chem. Rev.
8. 8)
  - 12. Li, X., He, J.: ‘Synthesis of raspberry-like SiO2–TiO2 nanoparticles toward antireflective and self-cleaning coatings’, ACS Appl. Mater. Inter., 2013, 5, (11), pp. 5282–5290 (doi: 10.1021/am401124j).
9. 9)
  - 13. Li, G., Yang, X.: ‘Facile synthesis of hollow polymer microspheres with movable cores with the aid of hydrogen-bonding interaction’, J. Phys. Chem. B, 2007, 111, (44), pp. 12781–12786 (doi: 10.1021/jp073566j).
10. 10)
  - 32. Sing, K.S.: ‘Reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity’, Pure Ure. Appl. Chem., 1985, 57, (4), pp. 603–619.
11. 11)
  - 24. Zimny, K., Roques-Carmes, T., Carteret, C., Stébé, M., Blin, J.: ‘Synthesis and photoactivity of ordered mesoporous titania with a semicrystalline framework’, J. Phys. Chem. C, 2012, 116, (11), pp. 6585–6594 (doi: 10.1021/jp212428k).
12. 12)
  - 19. Jiang, Y., Yan, Y., Zhang, W., Ni, L., Sun, Y., Yin, H.: ‘Synthesis of cauliflower-like ZnO–TiO2 composite porous film and photoelectrical properties’, Appl. Surf. Sci., 2011, 257, (15), pp. 6583–6589 (doi: 10.1016/j.apsusc.2011.02.082).
13. 13)
  - 7. Wang, Y., Li, B., Zhang, L., Song, H.: ‘Multifunctional mesoporous nanocomposites with magnetic, optical, and sensing features: synthesis, characterization, and their oxygen-sensing performance’, Langmuir, 2013, 29, (4), pp. 1273–1279 (doi: 10.1021/la304398c).
14. 14)
  - 8. He, L., Liu, Y., Liu, J., et al: ‘Core–shell noble-metal@metal-organic-framework nanoparticles with highly selective sensing property’, Angew. Chem. Int. Edit., 2013, 52, (13), pp. 3741–3745 (doi: 10.1002/anie.201209903).
15. 15)
  - 5. Chen, X., Liu, L., Peter, Y.Y., Mao, S.S.: ‘Increasing solar absorption for photocatalysis with black hydrogenated titanium dioxide nanocrystals’, Science, 2011, 331, (6018), pp. 746–750 (doi: 10.1126/science.1200448).
16. 16)
  - 30. Zhang, X., Zhang, F., Chan, K.Y.: ‘Synthesis of titania–silica mixed oxide mesoporous materials, characterization and photocatalytic properties’, Appl. Catal. A, Gen, 2005, 284, (1–2), pp. 193–198 (doi: 10.1016/j.apcata.2005.01.037).
17. 17)
  - 11. Luciani, C.V., Choi, K.Y.: ‘Mathematical modeling of polymer particles with a pomegranate-like internal structure via micro-dispersive polymerization in a geometrically confined reaction space’, Macromol. Theor. Simul., 2014, 23, (3), pp. 110–124 (doi: 10.1002/mats.201300128).
18. 18)
  - 20. Yang, X., Li, Q., Zhang, S., Zhong, X., Dai, Y., Luo, F.: ‘Electrochemical corrosion behaviors and protective properties of Ni–Co–TiO2 composite coating prepared on sintered NdFeB magnet’, Mater. Corros., 2010, 61, (7), pp. 618–625 (doi: 10.1002/maco.200905449).
19. 19)
  - W. Stöber , A. Fink , E. Bohn . Controlled growth of monodisperse silica spheres in the micron size range. J. Colloid Interface Sci. , 1 , 62 - 69
20. 20)
  - 4. Zhu, Y., Ikoma, T., Hanagata, N., Kaskel, S.: ‘Rattle-type Fe3O4@SiO2 hollow mesoporous spheres as carriers for drug delivery’, Small, 2010, 6, (3), pp. 471–478 (doi: 10.1002/smll.200901403).
21. 21)
  - 16. Yang, Y., Liu, J., Li, X., Liu, X., Yang, Q.: ‘Organosilane-assisted transformation from core–shell to yolk–shell nanocomposites’, Chem. Mater., 2011, 23, (16), pp. 3676–3684 (doi: 10.1021/cm201182d).
22. 22)
  - 3. Xu, Z., Wang, D., Guan, M., et al: ‘Photoluminescent silicon nanocrystal-based multifunctional carrier for pH-regulated drug delivery’, ACS Appl. Mater. Inter., 2012, 4, (7), pp. 3424–3431 (doi: 10.1021/am300877v).
23. 23)
  - 6. Ding, J., Li, B., Liu, Y., et al: ‘Fabrication of Fe3O4@ reduced graphene oxide composite via novel colloid electrostatic self-assembly process for removal of contaminants from water’, J. Mater. Chem. A, 2015, 3, (2), pp. 832–839 (doi: 10.1039/C4TA04297B).
24. 24)
  - 2. Deng, Y., Cai, Y., Sun, Z., et al: ‘Multifunctional mesoporous composite microspheres with well-designed nanostructure: a highly integrated catalyst system’, J. Am. Chem. Soc., 2010, 132, (24), pp. 8466–8473 (doi: 10.1021/ja1025744).
25. 25)
  - 24. Zhao, M.N., Zhou, G.W., Zhang, L., Li, X.Y., Li, T.D., Liu, F.F.: ‘Fabrication and photoactivity of a tunable-void SiO2–TiO2 core-shell structure on modified SiO2 nanospheres by grafting an amphiphilic diblock copolymer using ARGET ATRP’, Soft Mat., 2014, 10, pp. 1110–1120 (doi: 10.1039/C3SM52482E).
26. 26)
  - 21. Chen, J., Wang, D., Qi, J., et al: ‘Monodisperse hollow spheres with sandwich heterostructured shells as high-performance catalysts via an extended SiO2 template method’, Small, 2015, 11, (4), pp. 420–425 (doi: 10.1002/smll.201402423).
27. 27)
  - 9. Luciani, C.V., Choi, K.Y., Han, J.J., Jung, Y.: ‘Polymer particles with a pomegranate-like internal structure via micro-dispersive polymerization in a geometrically confined reaction space I. experimental study’, Polymer, 2011, 52, (4), pp. 942–948 (doi: 10.1016/j.polymer.2010.12.055).
28. 28)
  - 1. Yin, P., Zhao, M., Deng, C.: ‘High efficiency enrichment of low–abundance peptides by novel dual-platform graphene@SiO2@PMMA’, Nanoscale, 2012, 4, (22), pp. 6948–6950 (doi: 10.1039/c2nr31649h).
29. 29)
  - 31. Everett, D.: ‘Manual of symbols and terminology for physicochemical quantities and units, appendix II: definitions, terminology and symbols in colloid and surface chemistry’, Pure Ure. Appl. Chem., 1972, 31, (4), pp. 577–638.
30. 30)
  - 18. Cao, L., Chen, D., Caruso, R.A.: ‘Surface-metastable phase-initiated seeding and Ostwald ripening: a facile fluorine-free process towards spherical fluffy core/shell, yolk/shell, and hollow anatase nanostructures’, Angew. Chem., 2013, 125, (42), pp. 11192–11197 (doi: 10.1002/ange.201305819).
31. 31)
  - 10. Wang, X., Liu, D., Song, S., Zhang, H.: ‘Pt@CeO2 multicore@ shell self-assembled nanospheres: clean synthesis, structure optimization, and catalytic applications’, J. Am. Chem. Soc., 2013, 135, (42), pp. 15864–15872 (doi: 10.1021/ja4069134).
32. 32)
  - 17. Zhang, X., Mansouri, S., Clime, L., Ly, H., Yahia, L.H., Veres, T.: ‘Fe3O4–silica core–shell nanoporous particles for high-capacity pH-triggered drug delivery’, J. Mater. Chem., 2012, 22, (29), pp. 14450–14457 (doi: 10.1039/c2jm31749d).

Simple route to prepare different core–shell structured silica-based microspheres

References

Related content