Advertisement

Ionics

, Volume 24, Issue 3, pp 861–872 | Cite as

Towards sustainable energy. Photocatalysis of Cr-doped TiO2: 3. Effect of oxygen activity

  • Kazi Akikur Rahman
  • Tadeusz Bak
  • Armand Atanacio
  • Mihail Ionescu
  • Janusz NowotnyEmail author
Original Paper

Abstract

The present chain of five papers considers the concept of solar-to-chemical energy conversion using TiO2-based semiconductors. The series reports the effect of chromium on the key performance-related properties of polycrystalline TiO2 (rutile), including electronic structure, photocatalytic activity, intrinsic defect disorder, electrochemical coupling and surface vs. bulk properties. The present work reports the effect of oxygen activity in the oxide lattice on photocatalytic activity of pure and Cr-doped TiO2 (0.04 at% Cr). Processing of specimens included annealing at 1273 K in the gas phase of controlled oxygen activity in the range 10−12 Pa < p(O2) < 105 Pa. We show that the increase of oxygen activity results initially in a decrease of photocatalytic activity, minimum around the n-p transition point, and then increase assuming maximum at p(O2) = 105 Pa. The obtained results are considered in terms of a theoretical model that explains the effect of defect disorder on the reactivity of TiO2 with water. The minimum of the photocatalytic activity corresponds to the n-p transition point. The maximum of performance at high p(O2) is determined by increased concentration of titanium vacancies forming surface active sites.

Keywords

Defect disorder Oxygen activity Reactivity 

Notes

References

  1. 1.
    Rahman 1K A, Bak T, Atanacio A, Ionescu M, Nowotny, J (2017), Toward sustainable energy: photocatalysis of Cr-doped TiO2: 1. electronic structure, Ionics. DOI:  https://doi.org/10.1007/s11581-017-2369-2
  2. 2.
    Rahman KA, Bak T, Atanacio A, Ionescu M, Nowotny J (2017) Towards sustainable energy: photocatalysis of Cr-doped TiO2. 2. Effect of defect disorder, Ionics. DOI:  https://doi.org/10.1007/s11581-017-2370-9
  3. 3.
    Lee JS, You KH, Park CB (2012) Highly photoactive, low Bandgap TiO2 Nanoparticles wrapped by Graphene. Adv Mater 24(8):1084–1088CrossRefGoogle Scholar
  4. 4.
    Asahi R et al (2001) Visible-light photocatalysis in nitrogen-doped titanium oxides. Science 293(5528):269–271CrossRefGoogle Scholar
  5. 5.
    Chen D et al (2007) Carbon and nitrogen co-doped TiO2 with enhanced visible-light Photocatalytic activity. Ind Eng Chem Res 46(9):2741–2746CrossRefGoogle Scholar
  6. 6.
    Diaz-Uribe C, Vallejo W, Ramos W (2014) Methylene blue photocatalytic mineralization under visible irradiation on TiO2 thin films doped with chromium. Appl Surf Sci 319:121–127CrossRefGoogle Scholar
  7. 7.
    Hao W, James PL (2005) Effects of dopant states on photoactivity in carbon-doped TiO2. J Phys Condens Matter 17(21):L209CrossRefGoogle Scholar
  8. 8.
    Wilke K, Breuer H (1999) The influence of transition metal doping on the physical and photocatalytic properties of titania. J Photochem Photobiol A Chem 121(1):49–53CrossRefGoogle Scholar
  9. 9.
    Wang X et al (2005) Pyrogenic iron (III)-doped TiO2 nanopowders synthesized in RF thermal plasma: phase formation, defect structure, band gap, and magnetic properties. J Am Chem Soc 127(31):10982–10990CrossRefGoogle Scholar
  10. 10.
    Kröger F, Vink H (1956) Relations between the concentrations of imperfections in crystalline solids. Solid State Phys 3:307–435CrossRefGoogle Scholar
  11. 11.
    Nowotny J et al (2016) Electrical conductivity, thermoelectric power, and equilibration kinetics of Nb-doped TiO2. J Phys Chem A 120(34):6822–6837CrossRefGoogle Scholar
  12. 12.
    Bak T et al (2008) Charge transport in Cr-doped titanium dioxide. J Phys Chem C 112(18):7255–7262CrossRefGoogle Scholar
  13. 13.
    Jayamaha U et al (2015) Effect of oxygen activity on chromium segregation in Cr-doped TiO2 single crystal. Ionics 21(3):785–790CrossRefGoogle Scholar
  14. 14.
    Nowotny J et al (2016) Effect of oxygen activity on the n–p transition for pure and Cr-doped TiO2. J Phys Chem C 120(6):3221–3228CrossRefGoogle Scholar
  15. 15.
    Wendt S et al (2008) The role of interstitial sites in the Ti3d defect state in the band gap of titania. Science 320(5884):1755–1759CrossRefGoogle Scholar
  16. 16.
    Bak T, Nowotny J, Sucher NJ, Wachsman E (2011) Effect of crystal imperfections on reactivity and photoreactivity of TiO2 (rutile) with oxygen, water, and bacteria. J Phys Chem C 115(32):15711–15738CrossRefGoogle Scholar
  17. 17.
    Bak T et al (2008) Effect of prolonged oxidation on semiconducting properties of titanium dioxide. J Phys Chem C 112(34):13248–13257CrossRefGoogle Scholar
  18. 18.
    Nowotny M, Bak T, Nowotny J (2006) Electrical properties and defect chemistry of TiO2 single crystal. IV. Prolonged oxidation kinetics and chemical diffusion. J Phys Chem B 110(33):16302–16308CrossRefGoogle Scholar
  19. 19.
    Rahman, K.A., Bak, T., Atanacio, A., Ionescu, M., Liu, R. and Nowotny, J. (2017), Towards sustainable energy: photocatalysis of Cr-doped TiO2. 5. Effect of segregation on surface versus bulk composition. Ionics pp.1-9Google Scholar
  20. 20.
    Choudhury B, Choudhury A (2012) Dopant induced changes in structural and optical properties of Cr3+ doped TiO2 nanoparticles. Mater Chem Phys 132(2):1112–1118CrossRefGoogle Scholar
  21. 21.
    Yang K, Dai Y, Huang B (2009) Density functional characterization of the electronic structure and visible‐light absorption of Cr‐doped Anatase TiO2. ChemPhysChem 10(13):2327–2333CrossRefGoogle Scholar
  22. 22.
    Sasaki J, Peterson N, Hoshino K (1985) Tracer impurity diffusion in single-crystal rutile (TiO2− x). J Phys Chem Solids 46(11):1267–1283CrossRefGoogle Scholar
  23. 23.
    Kohler K et al (1993) Chromia supported on Titania: I. An EPR study of the chemical and structural changes occurring during catalyst genesis. J Catal 143(1):201–214CrossRefGoogle Scholar
  24. 24.
    Venezia A et al (1994) Characterization of chromium ion-doped titania by FTIR and XPS. J Catal 147(1):115–122CrossRefGoogle Scholar
  25. 25.
    Köhler K et al (1995) Chromium oxide supported on titania: preparation of highly dispersed Cr (III) systems by grafting. Langmuir 11(9):3423–3430CrossRefGoogle Scholar
  26. 26.
    Kim R et al (2014) Charge and magnetic states of rutile TiO2 doped with Cr ions. J Phys Condens Matter 26(14):146003CrossRefGoogle Scholar
  27. 27.
    Koh PW et al (2017) Photocatalytic degradation of photosensitizing and non-photosensitizing dyes over chromium doped titania photocatalysts under visible light. J Photochem Photobiol A Chem 332:215–223CrossRefGoogle Scholar
  28. 28.
    López R, Gómez R, Oros-Ruiz S (2011) Photophysical and photocatalytic properties of TiO2-Cr sol–gel prepared semiconductors. Catal Today 166(1):159–165CrossRefGoogle Scholar
  29. 29.
    Mardare D et al (2010) Undoped and Cr-doped TiO2 thin films obtained by spray pyrolysis. Thin Solid Films 518(16):4586–4589CrossRefGoogle Scholar
  30. 30.
    Santara B et al (2016) Mechanism of defect induced ferromagnetism in undoped and Cr doped TiO2 nanorods/nanoribbons. J Alloys Compd 661:331–344CrossRefGoogle Scholar
  31. 31.
    Wang L, Egerton TA (2013) The influence of chromium on photocatalysis of propan-2-ol and octadecanoic acid oxidation by rutile TiO2. J Photochem Photobiol A Chem 252:211–215CrossRefGoogle Scholar
  32. 32.
    Belaya E, Viktorov V (2008) Formation of solid solutions in the TiO2-Cr2O3 system. Inorg Mater 44(1):62–66CrossRefGoogle Scholar
  33. 33.
    Osterwalder J et al (2005) Growth of Cr-doped TiO2 films in the rutile and anatase structures by oxygen plasma assisted molecular beam epitaxy. Thin Solid Films 484(1):289–298CrossRefGoogle Scholar
  34. 34.
    Carpentier J-L, Lebrun A, Perdu F (1989) Point defects and charge transport in pure and chromium-doped rutile at 1273 K. J Phys Chem Solids 50(2):145–151CrossRefGoogle Scholar
  35. 35.
    Sambrano JR et al (1997) An ab initio study of oxygen vacancies and doping process of Nb and Cr atoms on TiO2 (110) surface models. Int J Quantum Chem 65(5):625–631CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany 2017

Authors and Affiliations

  • Kazi Akikur Rahman
    • 1
  • Tadeusz Bak
    • 1
  • Armand Atanacio
    • 2
  • Mihail Ionescu
    • 2
  • Janusz Nowotny
    • 1
    Email author
  1. 1.Solar Energy Technologies, School of Computing, Engineering and MathematicsWestern Sydney UniversityPenrithAustralia
  2. 2.Institute of Environmental ResearchAustralian Nuclear Science and Technology OrganisationKirraweeAustralia

Personalised recommendations