Journal of Materials Science

, Volume 54, Issue 7, pp 5266–5279 | Cite as

Enhanced photocatalytic performance of nanostructured TiO2 thin films through combined effects of polymer conjugation and Mo-doping

  • Yue Jiang
  • Wen-Fan Chen
  • Pramod Koshy
  • Charles Christopher Sorrell


Mo-doped TiO2 [≤ 0.20 wt% Mo; ≤ 0.10 mol% (metal basis)] with conjugated polyvinyl alcohol (TiO2/C-PVA) composite thin films was prepared by sol–gel dip coating on polished fused SiO2 substrates, followed by annealing at 180 °C for 4 h. These conditions were sufficient for solid solubility, despite the unusually low annealing temperature. The annealed thin films consisted of homogeneously distributed individual and slightly agglomerated anatase grains in a continuous C-PVA matrix characterized by the carbon double bond formed upon conjugation. The films exhibited drying shrinkage cracks, which increased consistently in extent with increasing Mo-doping concentration, effectively increasing the number of exposed TiO2 particles. Mo addition enhanced anatase nucleation, recrystallization, and growth at lower doping concentrations (up to ≤ 0.10 wt%), thereby increasing crystallinity. However, increasing doping levels (> 0.10 wt%) appeared to exceed the solubility limit, resulting in supersaturation and significant lattice destabilization. Mo-doping also caused the Ti2p XPS peaks to shift to lower binding energies and the Mo3d peaks to shift to higher binding energies. These data are consistent with thermodynamically unstable Ti4+ → Ti3+ conversion and thermodynamically stable Mo5+ → Mo6+ conversion, which are interpreted in terms of intervalence charge transfer (IVCT), in which charge compensation is achieved through majority Ti4+ → Ti3+ reduction plus Mo5+ → Mo6+ oxidation. Ti3+ concentration also reflects a direct correlation with the Mo-doping concentration and resultant IVCT within the Mo solubility limit and a reverse effect upon supersaturation. There is a correlation with the Eg but this can be attributed to recrystallization rather than a semiconducting effect. No effect of midgap state formation from enhancement of the \( {\text{V}}_{\text{O}}^{ \cdot \cdot } \) concentration is expected because IVCT is a redox effect only and dissolution of Mo5+ or Mo6+ would generate Ti vacancies. The methylene blue dye degradation data exhibited the same trend but at a significant level (90.6% degradation), thus indicating that the mechanism dominating the photocatalytic performance is the recrystallization of the anatase and/or the modification of the semiconducting properties induced by Mo-doping, as indicated by the trends in band gap.



The authors acknowledge the financial support of the Australian Research Council (ARC) (DP140103954) and the characterization facilities provided by the Mark Wainwright Analytical Centre at UNSW Sydney.


  1. 1.
    Macwan D, Dave PN, Chaturvedi S (2011) A review on nano-TiO2 sol–gel type syntheses and its applications. J Mater Sci 46(11):3669–3686. CrossRefGoogle Scholar
  2. 2.
    Zhu J, Chen F, Zhang J, Chen H, Anpo M (2006) Fe3+–TiO2 photocatalysts prepared by combining sol–gel method with hydrothermal treatment and their characterization. J Photochem Photobiol 180(1–2):196–204CrossRefGoogle Scholar
  3. 3.
    Fujishima A, Honda K (1972) Electrochemical photolysis of water at a semiconductor electrode. Nature 238(5358):37–38CrossRefGoogle Scholar
  4. 4.
    Ren H, Koshy P, Chen W-F, Qi S, Sorrell CC (2017) Photocatalytic materials and technologies for air purification. J Hazard Mater 325:340–366CrossRefGoogle Scholar
  5. 5.
    Sánchez B, Sánchez-Muñoz M, Muñoz-Vicente M, Cobas G, Portela R, Suárez S, González AE, Rodríguez N, Amils R (2012) Photocatalytic elimination of indoor air biological and chemical pollution in realistic conditions. Chemosphere 87(6):625–630CrossRefGoogle Scholar
  6. 6.
    Wei C, Lin WY, Zainal Z, Williams NE, Zhu K, Kruzic AP, Smith RL, Rajeshwar K (1994) Bactericidal activity of TiO2 photocatalyst in aqueous media: toward a solar-assisted water disinfection system. Environ Sci Technol 28(5):934–938CrossRefGoogle Scholar
  7. 7.
    Yu JC, Ho W, Yu J, Yip H, Wong PK, Zhao J (2005) Efficient visible-light-induced photocatalytic disinfection on sulfur-doped nanocrystalline titania. Environ Sci Technol 39(4):1175–1179CrossRefGoogle Scholar
  8. 8.
    Hanaor DA, Sorrell CC (2011) Review of the anatase to rutile phase transformation. J Mater Sci 46(4):855–874CrossRefGoogle Scholar
  9. 9.
    Lin M-Z, Chen H, Chen W-F, Nakaruk A, Koshy P, Sorrell CC (2014) Effect of single-cation doping and codoping with Mn and Fe on the photocatalytic performance of TiO2 thin films. Int J Hydrog Energy 39(36):21500–21511CrossRefGoogle Scholar
  10. 10.
    Chen W-F, Mofarah SS, Hanaor DAH, Koshy P, Chen HK, Jiang Y, Sorrell CC (2018) Enhancement of Ce/Cr codopant solubility and chemical homogeneity in TiO2 nanoparticles through sol–gel versus pechini syntheses. Inorg Chem 57:7279–7289CrossRefGoogle Scholar
  11. 11.
    Chen W-F, Koshy P, Adler L, Sorrell CC (2017) Photocatalytic activity of V-doped TiO2 thin films for the degradation of methylene blue and rhodamine B dye solutions. J Aust Ceram Soc 53(2):569–576CrossRefGoogle Scholar
  12. 12.
    Chung L, Chen W-F, Koshy P, Sorrell CC (2017) Effect of Ce-doping on the photocatalytic performance of TiO2 thin films. Mater Chem Phys 197:236–239CrossRefGoogle Scholar
  13. 13.
    Chen W-F, Koshy P, Huang Y, Adabifiroozjaei E, Yao Y, Sorrell CC (2016) Effects of precipitation, liquid formation, and intervalence charge transfer on the properties and photocatalytic performance of cobalt-or vanadium-doped TiO2 thin films. Int J Hydrog Energy 41(42):19025–19056CrossRefGoogle Scholar
  14. 14.
    Chen H-K, Chen W-F, Koshy P, Adabifiroozjaei E, Liu R, Sheppard LR, Sorrell CC (2016) Effect of tungsten-doping on the properties and photocatalytic performance of titania thin films on glass substrates. J Taiwan Inst Chem Eng 67:202–210CrossRefGoogle Scholar
  15. 15.
    Chen W-F, Koshy P, Sorrell CC (2015) Effect of intervalence charge transfer on photocatalytic performance of cobalt-and vanadium-codoped TiO2 thin films. Int J Hydrog Energy 40(46):16215–16229CrossRefGoogle Scholar
  16. 16.
    Devi LG, Murthy BN (2008) Characterization of Mo doped TiO2 and its enhanced photocatalytic activity under visible light. Catal Lett 125(3–4):320–330CrossRefGoogle Scholar
  17. 17.
    Chen W-F, Chen H, Koshy P, Nakaruk A, Sorrell CC (2018) Effect of doping on the properties and photocatalytic performance of titania thin films on glass substrates: single-ion doping with Cobalt or Molybdenum. Mater Chem Phys 205:334–346CrossRefGoogle Scholar
  18. 18.
    Štengl V, Bakardjieva S (2010) Molybdenum-doped anatase and its extraordinary photocatalytic activity in the degradation of orange II in the UV and vis regions. J Phys Chem Lett 114(45):19308–19317CrossRefGoogle Scholar
  19. 19.
    Tan K, Zhang H, Xie C, Zheng H, Gu Y, Zhang W (2010) Visible-light absorption and photocatalytic activity in molybdenum-and nitrogen-codoped TiO2. Catal Commun 11(5):331–335CrossRefGoogle Scholar
  20. 20.
    Devi LG, Kumar SG, Murthy BN, Kottam N (2009) Influence of Mn2+ and Mo6+ dopants on the phase transformations of TiO2 lattice and its photo catalytic activity under solar illumination. Catal Commun 10(6):794–798CrossRefGoogle Scholar
  21. 21.
    Lin CP, Chen H, Nakaruk A, Koshy P, Sorrell CC (2013) Effect of annealing temperature on the photocatalytic activity of TiO2 thin films. Energy Procedia 34:627–636CrossRefGoogle Scholar
  22. 22.
    Yan J, Wei T, Shao B, Fan Z, Qian W, Zhang M, Wei F (2010) Preparation of a graphene nanosheet/polyaniline composite with high specific capacitance. Carbon 48(2):487–493CrossRefGoogle Scholar
  23. 23.
    DeMerlis CC, Schoneker DR (2003) Review of the oral toxicity of polyvinyl alcohol (PVA). Food Chem Toxicol 41(3):319–326CrossRefGoogle Scholar
  24. 24.
    Faure B, Salazar-Alvarez G, Ahniyaz A, Villaluenga I, Berriozabal G, De Miguel YR, Bergström L (2013) Dispersion and surface functionalization of oxide nanoparticles for transparent photocatalytic and UV-protecting coatings and sunscreens. Sci Technol Adv Mater 14(2):023001CrossRefGoogle Scholar
  25. 25.
    Sun H, Cao Y, Feng L, Chen Y (2016) Immobilizing photogenerated electrons from graphitic carbon nitride for an improved visible-light photocatalytic activity. Sci Rep 6:22808CrossRefGoogle Scholar
  26. 26.
    Torres FG, Nazhat SN, Fadzullah SSM, Maquet V, Boccaccini AR (2007) Mechanical properties and bioactivity of porous PLGA/TiO2 nanoparticle-filled composites for tissue engineering scaffolds. Compos Sci Technol 67(6):1139–1147CrossRefGoogle Scholar
  27. 27.
    Cho S, Choi W (2001) Solid-phase photocatalytic degradation of PVC–TiO2 polymer composites. J Photochem Photobiol 143(2–3):221–228CrossRefGoogle Scholar
  28. 28.
    Langlet M, Kim A, Audier M, Herrmann JM (2002) Sol–gel preparation of photocatalytic TiO2 films on polymer substrates. J Sol-Gel Sci Technol 25(3):223–234CrossRefGoogle Scholar
  29. 29.
    Nakata K, Ochilai T, Murakami T, Fujishima A (2012) Photoenergy conversion with TiO2 photocatalysis: new materials and recent applications. Electrochim Acta 84:103–111CrossRefGoogle Scholar
  30. 30.
    Van Hal PA, Christiaans MP, Wienk MM, Kroon JM, Janssen RA (1999) Photoinduced electron transfer from conjugated polymers to TiO2. J Phys Chem B 103(21):4352–4359CrossRefGoogle Scholar
  31. 31.
    Li X, Wang D, Luo Q, An J, Wang Y, Cheng G (2008) Surface modification of titanium dioxide nanoparticles by polyaniline via an in situ method. J Chem Technol Biotechnol 83(11):1558–1564CrossRefGoogle Scholar
  32. 32.
    Wang Y, Zhong M, Chen F, Yang J (2009) Visible light photocatalytic activity of TiO2/D-PVA for MO degradation. Appl Catal B 90(1–2):249–254CrossRefGoogle Scholar
  33. 33.
    Kuang T, Fu D, Chang L, Yang Z, Yang J, Fan P, Zhong M, Chen F, Peng X (2016) Enhanced photocatalysis of yittium-doped TiO2/D-PVA composites: degradation of methyl orange (MO) and PVC film. Sci Adv Mater 8(6):1286–1292CrossRefGoogle Scholar
  34. 34.
    Nair PB, Justinvictor VB, Daniel GP, Joy K, Ramakrishnan V, Kumar DD, Thomas PV (2014) Structural, optical, photoluminescence and photocatalytic investigations on Fe doped TiO2 thin films. Thin Solid Films 550:121–127CrossRefGoogle Scholar
  35. 35.
    Cordischi D, Burriesci N, D’Alba F, Petrera M, Polizzotti G, Schiavello M (1985) Structural characterization of Fe/Ti oxide photocatalysts by X-ray, ESR, and Mössbauer methods. J Solid State Chem 56(2):182–190CrossRefGoogle Scholar
  36. 36.
    Shinde SR, Ogale SB, Sarma SD, Simpson JR, Drew HD, Lofland SE, Lanci C, Buban JP, Browning ND, Kulkarni VN, Higgins J (2003) Ferromagnetism in laser deposited anatase Ti1−x Cox O2−δ films. Phys Rev B 67(11):115211CrossRefGoogle Scholar
  37. 37.
    Tauc J, Menth A (1972) States in the gap. J Non-Cryst Solids 8:569–585CrossRefGoogle Scholar
  38. 38.
    Wold A (1993) Photocatalytic Properties of TiO2. Chem Mater 5(3):280–283CrossRefGoogle Scholar
  39. 39.
    Kingery WD, Bowen HK, Uhlmann DR (1976) Introduction to ceramics, 2nd edn. Wiley, New YorkGoogle Scholar
  40. 40.
    Alhomoudi IA, Newaz G (2009) Residual stresses and Raman shift relation in anatase TiO2 thin film. Thin Solid Films 517(15):4372–4378CrossRefGoogle Scholar
  41. 41.
    Shannon RD (1976) Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta Crystallogr A 32(5):751–767CrossRefGoogle Scholar
  42. 42.
    Song Y, Zhang J, Yang H, Jiang L, Dan Y, Le Rendu P, Nguyen TP (2016) Photocatalytic activity of TiO2 based composite films by porous conjugated polymer coating of nanoparticles. Mater Sci Semicond Process 42:54–57CrossRefGoogle Scholar
  43. 43.
    Hegedűs P, Szabó-Bárdos E, Horváth O, Szabó P, Horváth K (2017) Investigation of a TiO2 photocatalyst immobilized with poly (vinyl alcohol). Catal Today 284:179–186CrossRefGoogle Scholar
  44. 44.
    Yang H, Zhang J, Song Y, Xu S, Jiang L, Dan Y (2015) Visible light photo-catalytic activity of C-PVA/TiO2 composites for degrading rhodamine B. Appl Surf Sci 324:645–651CrossRefGoogle Scholar
  45. 45.
    Zhang J, Song Y, Yang H, Xu S, Jiang L, Dan Y (2013) TiO2/T-PVA composites immobilized on cordierite: structure and photocatalytic activity for degrading RhB Under visible light. Water Air Soil Pollut 224(7):1555CrossRefGoogle Scholar
  46. 46.
    Yu J, Zhao X, Zhao Q (2001) Photocatalytic activity of nanometer TiO2 thin films prepared by the sol–gel method. Mater Chem Phys 69(1–3):25–29CrossRefGoogle Scholar
  47. 47.
    Shirkhanzadeh M (1995) XRD and XPS characterization of superplastic TiO2 coatings prepared on Ti6Al4V surgical alloy by an electrochemical method. J Mater Sci Mater Med 6(4):206–210CrossRefGoogle Scholar
  48. 48.
    Nakamura I, Negishi N, Kutsuna S, Ihara T, Sugihara S, Takeuchi K (2000) Role of oxygen vacancy in the plasma-treated TiO2 photocatalyst with visible light activity for NO removal. J Mol Catal A: Chem 161(1–2):205–212CrossRefGoogle Scholar
  49. 49.
    Wang S, Bai LN, Sun HM, Jiang Q, Lian JS (2013) Structure and photocatalytic property of Mo-doped TiO2 nanoparticles. Powder Technol 244:9–15CrossRefGoogle Scholar
  50. 50.
    Bevy LP (2005) New developments in catalysis research. Nova Publishers, New YorkGoogle Scholar
  51. 51.
    Naumkin AV, Kraut-Vass A, Gaarenstroom SW, Powell CJ (2012) NIST X-ray photoelectron spectroscopy database, NIST Standard Reference Database 20, Version 4.1., Washington: US Department of CommerceGoogle Scholar
  52. 52.
    Chen W-F, Koshy P, Sorrell CC (2016) Effects of film topology and contamination as a function of thickness on the photo-induced hydrophilicity of transparent TiO2 thin films deposited on glass substrates by spin coating. J Mater Sci 51(5):2465–2480CrossRefGoogle Scholar
  53. 53.
    Spangler CW (1999) Recent development in the design of organic materials for optical power limiting. J Mater Chem 9(9):2013–2020CrossRefGoogle Scholar
  54. 54.
    Eufinger K, Poelman D, Poelman H, De Gryse R, Marin GB (2007) Photocatalytic activity of dc magnetron sputter deposited amorphous TiO2 thin films. Appl Surf Sci 254(1):148–152CrossRefGoogle Scholar
  55. 55.
    Ren M, Frimmel FH, Abbt-Braun G (2015) Multi-cycle photocatalytic degradation of bezafibrate by a cast polyvinyl alcohol/titanium dioxide (PVA/TiO2) hybrid film. J Mol Catal A: Chem 400:42–48CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  • Yue Jiang
    • 1
  • Wen-Fan Chen
    • 1
  • Pramod Koshy
    • 1
  • Charles Christopher Sorrell
    • 1
  1. 1.School of Materials Science and EngineeringUNSW SydneySydneyAustralia

Personalised recommendations