Advertisement

Nano Research

, Volume 9, Issue 11, pp 3478–3493 | Cite as

Enhanced CH4 yield by photocatalytic CO2 reduction using TiO2 nanotube arrays grafted with Au, Ru, and ZnPd nanoparticles

  • Piyush Kar
  • Samira Farsinezhad
  • Najia Mahdi
  • Yun Zhang
  • Uchenna Obuekwe
  • Himani Sharma
  • Jing Shen
  • Natalia Semagina
  • Karthik Shankar
Research Article

Abstract

Metal nanoparticle (NP) co-catalysts on metal oxide semiconductor supports are attracting attention as photocatalysts for a variety of chemical reactions. Related efforts seek to make and use Pt-free catalysts. In this regard, we report here enhanced CH4 formation rates of 25 and 60 μmol·g–1·h–1 by photocatalytic CO2 reduction using hitherto unused ZnPd NPs as well as Au and Ru NPs. The NPs are formed by colloidal synthesis and grafted onto short n-type anatase TiO2 nanotube arrays (TNAs), grown anodically on transparent glass substrates. The interfacial electric fields in the NP-grafted TiO2 nanotubes were probed by ultraviolet photoelectron spectroscopy (UPS). Au NP-grafted TiO2 nanotubes (Au-TNAs) showed no band bending, but a depletion region was detected in Ru NP-grafted TNAs (Ru-TNAs) and an accumulation layer was observed in ZnPd NP-grafted TNAs (ZnPd-TNAs). Temperature programmed desorption (TPD) experiments showed significantly greater CO2 adsorption on NP-grafted TNAs. TNAs with grafted NPs exhibit broader and more intense UV–visible absorption bands than bare TNAs. We found that CO2 photoreduction by nanoparticle-grafted TNAs was driven not only by ultraviolet photons with energies greater than the TiO2 band gap, but also by blue photons close to and below the anatase band edge. The enhanced rate of CO2 reduction is attributed to superior use of blue photons in the solar spectrum, excellent reactant adsorption, efficient charge transfer to adsorbates, and low recombination losses.

Keywords

metal nanoparticles (NPs) TiO2 nanotube arrays (TNAs) colloidal synthesis band bending built-in potential photocatalytic CO2 reduction semiconductor heterojunctions 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Supplementary material

12274_2016_1225_MOESM1_ESM.pdf (3.1 mb)
Enhanced CH4 yield by photocatalytic CO2 reduction using TiO2 nanotube arrays grafted with Au, Ru, and ZnPd nanoparticles

References

  1. [1]
    Mulvihill, M. J.; Beach, E. S.; Zimmerman, J. B.; Anastas, P. T. Green chemistry and green engineering: A framework for sustainable technology development. Ann. Rev. Environ. Resour. 2011, 36, 271–293.CrossRefGoogle Scholar
  2. [2]
    Leitner, W. Carbon dioxide as a raw material: The synthesis of formic acid and its derivatives from CO2. Angew. Chem, Int. Ed. 1995, 34, 2207–2221.CrossRefGoogle Scholar
  3. [3]
    Yui, T.; Kan, A.; Saitoh, C.; Koike, K.; Ibusuki, T.; Ishitani, O. Photochemical reduction of CO2 using TiO2: Effects of organic adsorbates on TiO2 and deposition of Pd onto TiO2. ACS Appl. Mater. Interfaces 2011, 3, 2594–2600.CrossRefGoogle Scholar
  4. [4]
    Manzi, A.; Simon, T.; Sonnleitner, C.; Dö blinger, M.; Wyrwich, R.; Stern, O.; Stolarczyk, J. K.; Feldmann, J. Light-induced cation exchange for copper sulfide based CO2 reduction. J. Am. Chem. Soc. 2015, 137, 14007–14010.CrossRefGoogle Scholar
  5. [5]
    Kar, P.; Farsinezhad, S.; Zhang, X. J.; Shankar, K. Anodic Cu2S and CuS nanorod and nanowall arrays: Preparation, properties and application in CO2 photoreduction. Nanoscale 2014, 6, 14305–14318.CrossRefGoogle Scholar
  6. [6]
    Zhang, X. J.; Han, F.; Shi, B.; Farsinezhad, S.; Dechaine, G. P.; Shankar, K. Photocatalytic conversion of diluted CO2 into light hydrocarbons using periodically modulated multiwalled nanotube arrays. Angew. Chem. 2012, 124, 12904–12907.CrossRefGoogle Scholar
  7. [7]
    Wang, S. B.; Hou, Y. D.; Wang, X. C. Development of a stable MnCO2O4 cocatalyst for photocatalytic CO2 reduction with visible light. ACS Appl. Mater. Interfaces 2015, 7, 4327–4335.CrossRefGoogle Scholar
  8. [8]
    Wang, S. B.; Wang, X. C. Photocatalytic CO2 reduction by CdS promoted with a zeolitic imidazolate framework. Appl. Catal. B: Environ. 2015, 162, 494–500.CrossRefGoogle Scholar
  9. [9]
    Zhai, Q. G.; Xie, S. J.; Fan, W. Q.; Zhang, Q. H.; Wang, Y.; Deng, W. P.; Wang, Y. Photocatalytic conversion of carbon dioxide with water into methane: Platinum and copper(I) oxide co-catalysts with a core–shell structure. Angew. Chem. 2013, 125, 5888–5891.CrossRefGoogle Scholar
  10. [10]
    Tu, W. G.; Zhou, Y.; Zou, Z. G. Photocatalytic conversion of CO2 into renewable hydrocarbon fuels: State-of-the-art accomplishment, challenges, and prospects. Adv. Mater. 2014, 26, 4607–4626.CrossRefGoogle Scholar
  11. [11]
    Marszewski, M.; Cao, S. W.; Yu, J. G.; Jaroniec, M. Semiconductor-based photocatalytic CO2 conversion. Mater. Horiz. 2015, 2, 261–278.CrossRefGoogle Scholar
  12. [12]
    Habisreutinger, S. N.; Schmidt-Mende, L.; Stolarczyk, J. K. Photocatalytic reduction of CO2 on TiO2 and other semiconductors. Angew. Chem., Int. Ed. 2013, 52, 7372–7408.CrossRefGoogle Scholar
  13. [13]
    Wettstein, S. G.; Bond, J. Q.; Alonso, D. M.; Pham, H. N.; Datye, A. K.; Dumesic, J. A. RuSn bimetallic catalysts for selective hydrogenation of levulinic acid to valerolactone. Appl. Catal. B: Environ. 2012, 117–118, 321–329.CrossRefGoogle Scholar
  14. [14]
    Fu, J. L.; Yang, K. X.; Ma, C. J.; Zhang, N. W.; Gai, H. J.; Zheng, J. B.; Chen, B. H. Bimetallic Ru–Cu as a highly active, selective and stable catalyst for catalytic wet oxidation of aqueous ammonia to nitrogen. Appl. Catal. B: Environ. 2016, 184, 216–222.CrossRefGoogle Scholar
  15. [15]
    Ziaei-azad, H.; Yin, C.-X.; Shen, J.; Hu, Y. F.; Karpuzov, D.; Semagina, N. Size- and structure-controlled mono- and bimetallic Ir–Pd nanoparticles in selective ring opening of indan. J. Catal. 2013, 300, 113–124.CrossRefGoogle Scholar
  16. [16]
    Zielinska-Jurek, A.; Kowalska, E.; Sobczak, J. W.; Lisowski, W.; Ohtani, B.; Zaleska, A. Preparation and characterization of monometallic (Au) and bimetallic (Ag/Au) modifiedtitania photocatalysts activated by visible light. Appl. Catal. B: Environ. 2011, 101, 504–514.CrossRefGoogle Scholar
  17. [17]
    Gallo, A.; Marelli, M.; Psaro, R.; Gombac, V.; Montini, T.; Fornasiero, P.; Pievo, R.; Dal Santo, V. Bimetallic Au–Pt/TiO2 photocatalysts active under UV-A and simulated sunlight for H2 production from ethanol. Green Chem. 2012, 14, 330–333.CrossRefGoogle Scholar
  18. [18]
    Tsukamoto, D.; Shiro, A.; Shiraishi, Y.; Sugano, Y.; Ichikawa, S.; Tanaka, S.; Hirai, T. Photocatalytic H2O2 production from ethanol/O2 system using TiO2 loaded with Au–Ag bimetallic alloy nanoparticles. ACS Catal. 2012, 2, 599–603.CrossRefGoogle Scholar
  19. [19]
    Amirsolaimani, B.; Zhang, X. J.; Han, F.; Farsinezhad, S.; Mohammadpour, A.; Dechaine, G.; Shankar, K. Effect of the nature of the metal co-catalyst on CO2 photoreduction using fast-grown periodically modulated titanium dioxide nanotube arrays (PMTiNTs). MRS Proc. 2013, 1578, DOI: 10.1557/opl.2013.841.Google Scholar
  20. [20]
    Feng, S. C.; Wang, M.; Zhou, Y.; Li, P.; Tu, W. G.; Zou, Z. G. Double-shelled plasmonic Ag-TiO2 hollow spheres toward visible light-active photocatalytic conversion of CO2 into solar fuel. APL Mater. 2015, 3, 104416.CrossRefGoogle Scholar
  21. [21]
    Kang, Q.; Wang, T.; Li, P.; Liu, L. Q.; Chang, K.; Li, M.; Ye, J. H. Photocatalytic reduction of carbon dioxide by hydrous hydrazine over Au–Cu alloy nanoparticles supported on SrTiO3/TiO2 coaxial nanotube arrays. Angew. Chem. 2015, 127, 855–859.CrossRefGoogle Scholar
  22. [22]
    Farsinezhad, S.; Sharma, H.; Shankar, K. Interfacial band alignment for photocatalytic charge separation in TiO2 nanotube arrays coated with CuPt nanoparticles. Phys. Chem. Chem. Phys. 2015, 17, 29723–29733.CrossRefGoogle Scholar
  23. [23]
    Xiao, F. X.; Miao, J. W.; Tao, H. B.; Hung, S. F.; Wang, H. Y.; Yang, H. B.; Chen, J. Z.; Chen, R.; Liu, B. One-dimensional hybrid nanostructures for heterogeneous photocatalysis and photoelectrocatalysis. Small 2015, 11, 2115–2131.CrossRefGoogle Scholar
  24. [24]
    Varghese, O. K.; Paulose, M.; LaTempa, T. J.; Grimes, C. A. High-rate solar photocatalytic conversion of CO2 and water vapor to hydrocarbon fuels. Nano Lett. 2009, 9, 731–737.CrossRefGoogle Scholar
  25. [25]
    Paramasivam, I.; Jha, H.; Liu, N.; Schmuki, P. A review of photocatalysis using self-organized TiO2 nanotubes and other ordered oxide nanostructures. Small 2012, 8, 3073–3103.CrossRefGoogle Scholar
  26. [26]
    Chen, X. B.; Mao, S. S. Titanium dioxide nanomaterials: Synthesis, properties, modifications, and applications. Chem. Rev. 2007, 107, 2891–2959.CrossRefGoogle Scholar
  27. [27]
    Kar, P.; Zhang, Y.; Farsinezhad, S.; Mohammadpour, A.; Wiltshire, B. D.; Sharma, H.; Shankar, K. Rutile phase nand p-type anodic titania nanotube arrays with square-shaped pore morphologies. Chem. Commun. 2015, 51, 7816–7819.CrossRefGoogle Scholar
  28. [28]
    Mor, G. K.; Shankar, K.; Paulose, M.; Varghese, O. K.; Grimes, C. A. Enhanced photocleavage of water using titania nanotube arrays. Nano Lett. 2005, 5, 191–195.CrossRefGoogle Scholar
  29. [29]
    Kocí, K.; Obalová, L.; Matejová, L.; Plachá, D.; Lacný, Z.; Jirkovský, J.; Šolcová, O. Effect of TiO2 particle size on the photocatalytic reduction of CO2. Appl. Catal. B: Environ. 2009, 89, 494–502.CrossRefGoogle Scholar
  30. [30]
    Murugesan, S.; Smith, Y. R.; Subramanian, V. Hydrothermal synthesis of Bi12TiO20 nanostrucutures using anodized TiO2 nanotubes and its application in photovoltaics. The J. Phys. Chem. Lett. 2010, 1, 1631–1636.CrossRefGoogle Scholar
  31. [31]
    Yu, J. G.; Low, J. X.; Xiao, W.; Zhou, P.; Jaroniec, M. Enhanced photocatalytic CO2-reduction activity of anatase TiO2 by coexposed {001} and {101} facets. J. Am. Chem. Soc. 2014, 136, 8839–8842.CrossRefGoogle Scholar
  32. [32]
    Xie, T.-F.; Wang, D.-J.; Zhu, L.-J.; Li, T.-J.; Xu, Y.-J. Application of surface photovoltage technique in photocatalysis studies on modified TiO2 photo-catalysts for photo-reduction of CO2. Mater. Chem. Phys. 2001, 70, 103–106.CrossRefGoogle Scholar
  33. [33]
    Tseng, I.-H.; Wu, J. C. S.; Chou, H.-Y. Effects of sol–gel procedures on the photocatalysis of Cu/TiO2 in CO2 photoreduction. J. Catal. 2004, 221, 432–440.CrossRefGoogle Scholar
  34. [34]
    Farsinezhad, S.; Mohammadpour, A.; Dalrymple, A. N.; Geisinger, J.; Kar, P.; Brett, M. J.; Shankar, K. Transparent anodic TiO2 nanotube arrays on plastic substrates for disposable biosensors and flexible electronics. J. Nanosci. Nanotechnol. 2013, 13, 2885–2891.CrossRefGoogle Scholar
  35. [35]
    Farsinezhad, S.; Dalrymple, A. N.; Shankar, K. Toward single-step anodic fabrication of monodisperse TiO2 nanotube arrays on non-native substrates. Phys. Status Solidi (a) 2014, 211, 1113–1121.CrossRefGoogle Scholar
  36. [36]
    Mohammadpour, A.; Kar, P.; Wiltshire, B. D.; Askar, A. M.; Shankar, K. Electron transport, trapping and recombination in anodic TiO2 nanotube arrays. Curr. Nanosci. 2015, 11, 593–614.CrossRefGoogle Scholar
  37. [37]
    Shen, J.; Semagina, N. Iridium- and platinum-free ring opening of indan. ACS Catal. 2014, 4, 268–279.CrossRefGoogle Scholar
  38. [38]
    Wang, Y.; Toshima, N. Preparation of Pd-Pt bimetallic colloids with controllable core/shell structures. J. Phys. Chem. B 1997, 101, 5301–5306.CrossRefGoogle Scholar
  39. [39]
    Xu, X. J.; Pacey, P. D. Oligomerization and cyclization reactions of acetylene. Phys. Chem. Chem. Phys. 2005, 7, 326–333.CrossRefGoogle Scholar
  40. [40]
    Wang, W.-N.; An, W.-J.; Ramalingam, B.; Mukherjee, S.; Niedzwiedzki, D. M.; Gangopadhyay, S.; Biswas, P. Size and structure matter: Enhanced CO2 photoreduction efficiency by size-resolved ultrafine Pt nanoparticles on TiO2 single crystals. J. Am. Chem. Soc. 2012, 134, 11276–11281.CrossRefGoogle Scholar
  41. [41]
    Hodak, J. H.; Henglein, A.; Hartland, G. V. Photophysics of nanometer sized metal particles: Electron–phonon coupling and coherent excitation of breathing vibrational modes. J. Phys. Chem. B 2000, 104, 9954–9965.CrossRefGoogle Scholar
  42. [42]
    Sneed, B. T.; Young, A. P.; Tsung, C.-K. Building up strain in colloidal metal nanoparticle catalysts. Nanoscale 2015, 7, 12248–12265.CrossRefGoogle Scholar
  43. [43]
    Shen, J.; Yin, X.; Karpuzov, D.; Semagina, N. PVP-stabilized mono- and bimetallic Ru nanoparticles for selective ring opening. Catal. Sci. Technol. 2013, 3, 208–221.CrossRefGoogle Scholar
  44. [44]
    Ziaei-Azad, H.; Semagina, N. Bimetallic catalysts: Requirements for stabilizing PVP removal depend on the surface composition. Appl. Catal. A: Gen. 2014, 482, 327–335.CrossRefGoogle Scholar
  45. [45]
    Joo, S. H.; Park, J. Y.; Renzas, J. R.; Butcher, D. R.; Huang, W. Y.; Somorjai, G. A. Size effect of ruthenium nanoparticles in catalytic carbon monoxide oxidation. Nano Lett. 2010, 10, 2709–2713.CrossRefGoogle Scholar
  46. [46]
    Reyes, P.; König, M. E.; Pecchi, G.; Concha, I.; López Granados, M.; Fierro, J. L. G. o-Xylene hydrogenation on supported ruthenium catalysts. Catal. Lett. 1997, 46, 71–75.Google Scholar
  47. [47]
    Qian, K.; Sweeny, B. C.; Johnston-Peck, A. C.; Niu, W. X.; Graham, J. O.; DuChene, J. S.; Qiu, J. J.; Wang, Y.-C.; Engelhard, M. H.; Su, D. et al. Surface plasmon-driven water reduction: Gold nanoparticle size matters. J. Am. Chem. Soc. 2014, 136, 9842–9845.CrossRefGoogle Scholar
  48. [48]
    Murdoch, M.; Waterhouse, G. I. N.; Nadeem, M. A.; Metson, J. B.; Keane, M. A.; Howe, R. F.; Llorca, J.; Idriss, H. The effect of gold loading and particle size on photocatalytic hydrogen production from ethanol over Au/TiO2 nanoparticles. Nat. Chem. 2011, 3, 489–492.Google Scholar
  49. [49]
    Rajan, A.; MeenaKumari, M.; Philip, D. Shape tailored green synthesis and catalytic properties of gold nanocrystals. Spectrochim. Acta A: Mol. Biomol. Spectrosc. 2014, 118, 793–799.CrossRefGoogle Scholar
  50. [50]
    Dagle, R. A.; Chin, Y.-H.; Wang, Y. The effects of PdZn crystallite size on methanol steam reforming. Top. Catal. 2007, 46, 358–362.CrossRefGoogle Scholar
  51. [51]
    Karim, A.; Conant, T.; Datye, A. The role of PdZn alloy formation and particle size on the selectivity for steam reforming of methanol. J. Catal. 2006, 243, 420–427.CrossRefGoogle Scholar
  52. [52]
    Kruse, N.; Chenakin, S. XPS characterization of Au/TiO2 catalysts: Binding energy assessment and irradiation effects. Appl. Catal. A: Gen. 2011, 391, 367–376.CrossRefGoogle Scholar
  53. [53]
    Sobczak, J. W.; Andreeva, D. XPS study of Au/TiO2 catalytic systems. Stud. Surf. Sci. Catal. 2000, 130, 3303–3308.Google Scholar
  54. [54]
    Lee, S.; Fan, C. Y.; Wu, T. P.; Anderson, S. L. Agglomeration, support effects, and CO adsorption on Au/TiO2 (110) prepared by ion beam deposition. Surf. Sci. 2005, 578, 5–19.CrossRefGoogle Scholar
  55. [55]
    Elmasides, C.; Kondarides, D. I.; Grünert, W.; Verykios, X. E. XPS and FTIR study of Ru/Al2O3 and Ru/TiO2 catalysts: Reduction characteristics and interaction with a methaneoxygen mixture. J. Phys. Chem. B 1999, 103, 5227–5239.CrossRefGoogle Scholar
  56. [56]
    Semagina, N.; Renken, A.; Laub, D.; Kiwi-Minsker, L. Synthesis of monodispersed palladium nanoparticles to study structure sensitivity of solvent-free selective hydrogenation of 2-methyl-3-butyn-2-ol. J. Catal. 2007, 246, 308–314.CrossRefGoogle Scholar
  57. [57]
    Morozov, I. G.; Belousova, O. V.; Ortega, D.; Mafina, M.-K.; Kuznetcov, M. V. Structural, optical, XPS and magnetic properties of Zn particles capped by ZnO nanoparticles. J. Alloys Compd. 2015, 633, 237–245.CrossRefGoogle Scholar
  58. [58]
    Armbrüster, M.; Behrens, M.; Föttinger, K.; Friedrich, M.; Gaudry, É.; Matam, S. K.; Sharma, H. R. The intermetallic compound ZnPd and its role in methanol steam reforming. Catal. Rev. 2013, 55, 289–367.CrossRefGoogle Scholar
  59. [59]
    Grimes, C. A.; Mor, G. K. Material properties of TiO2 nanotube arrays: Structural, elemental, mechanical, optical and electrical. In TiO2 Nanotube Arrays; Springer: New York, 2009; pp 67–113.Google Scholar
  60. [60]
    Sexton, B. A.; Hughes, A. E.; Foger, K. XPS investigation of strong metal-support interactions on Group IIIa–Va oxides. J. Catal. 1982, 77, 85–93.Google Scholar
  61. [61]
    Shpiro, E. S.; Dysenbina, B. B.; Tkachenko, O. P.; Antoshin, G. V.; Minachev, K. M. Strong metal-support interaction: The role of electronic and geometric factors in real MeTiO2 catalysts. J. Catal. 1988, 110, 262–274.CrossRefGoogle Scholar
  62. [62]
    Lee, K. B.; Lee, K. H.; Cha, J. O.; Ahn, J. S. Ti–O binding states of resistive switching TiO2 thin films prepared by reactive magnetron sputtering. J. Korean Phys. Soc. 2008, 53, 1996–2001.Google Scholar
  63. [63]
    Sasan, K.; Zuo, F.; Wang, Y.; Feng, P. Y. Self-doped Ti3+–TiO2 as a photocatalyst for the reduction of CO2 into a hydrocarbon fuel under visible light irradiation. Nanoscale 2015, 7, 13369–13372.CrossRefGoogle Scholar
  64. [64]
    Indrakanti, V. P.; Kubicki, J. D.; Schobert, H. H. Photoinduced activation of CO2 on Ti-based heterogeneous catalysts: Current state, chemical physics-based insights and outlook. Energy Environ. Sci. 2009, 2, 745–758.CrossRefGoogle Scholar
  65. [65]
    Tanaka, K.; Miyahara, K.; Toyoshima, I. Adsorption of carbon dioxide on titanium dioxide and platinum/titanium dioxide studied by X-ray photoelectron spectroscopy and Auger electron spectroscopy. J. Phys. Chem. 1984, 88, 3504–3508.CrossRefGoogle Scholar
  66. [66]
    Rasko, J.; Solymosi, F. Infrared spectroscopic study of the photoinduced activation of CO2 on TiO2 and Rh/TiO2 catalysts. J. Phys. Chem. 1994, 98, 7147–7152.CrossRefGoogle Scholar
  67. [67]
    Kaneco, S.; Ohta, K.; Shimizu, Y.; Mizuno, T. Photocatalytic reduction of high pressure carbon dioxide using TiO2 powders. In Recent Research Developments in Photochemistry and Photobiology; 1998; pp 91–100.Google Scholar
  68. [68]
    Dey, G. R. Chemical reduction of CO2 to different products during photo catalytic reaction on TiO2 under diverse conditions: An overview. J. Nat. Gas Chem. 2007, 16, 217–226.CrossRefGoogle Scholar
  69. [69]
    Neatu, S; Maciá-Agulló, J. A.; Concepción, P.; Garcia, H. Gold–copper nanoalloys supported on TiO2 as photocatalysts for CO2 reduction by water. J. Am. Chem. Soc. 2014, 136, 15969–15976.CrossRefGoogle Scholar
  70. [70]
    Liu, L. J.; Gao, F.; Zhao, H. L.; Li, Y. Tailoring Cu valence and oxygen vacancy in Cu/TiO2 catalysts for enhanced CO2 photoreduction efficiency. Appl. Catal. B: Environ. 2013, 134-135, 349–358.CrossRefGoogle Scholar
  71. [71]
    Zhang, Z. Y.; Wang, Z.; Cao, S.-W.; Xue, C. Au/Pt nanoparticle-decorated TiO2 nanofibers with plasmonenhanced photocatalytic activities for solar-to-fuel conversion. J. Phys. Chem. C 2013, 117, 25939–25947.CrossRefGoogle Scholar
  72. [72]
    Tu, W. G.; Zhou, Y.; Liu, Q.; Yan, S. C.; Bao, S. S.; Wang, X. Y.; Xiao, M.; Zou, Z. G. An in situ simultaneous reduction-hydrolysis technique for fabrication of TiO2- graphene 2D sandwich-like hybrid nanosheets: Graphenepromoted selectivity of photocatalytic-driven hydrogenation and coupling of CO2 into methane and ethane. Adv. Funct. Mater. 2013, 23, 1743–1749.CrossRefGoogle Scholar
  73. [73]
    Zarifi, M. H.; Mohammadpour, A.; Farsinezhad, S.; Wiltshire, B. D.; Nosrati, M.; Askar, A. M.; Daneshmand, M.; Shankar, K. Time-resolved microwave photoconductivity (TRMC) using planar microwave resonators: Application to the study of long-lived charge pairs in photoexcited titania nanotube arrays. J. Phys. Chem. C 2015, 119, 14358–14365.Google Scholar
  74. [74]
    Fàbrega, C.; Hernández-Ramírez, F.; Prades, J. D.; Jiménez- Díaz, R.; Andreu, T.; Morante, J. R. On the photoconduction properties of low resistivity TiO2 nanotubes. Nanotechnology 2010, 21, 445703.CrossRefGoogle Scholar
  75. [75]
    Zou, J. P.; Zhang, Q.; Huang, K.; Marzari, N. Ultraviolet photodetectors based on anodic TiO2 nanotube arrays. J. Phys. Chem. C 2010, 114, 10725–10729.CrossRefGoogle Scholar
  76. [76]
    Liu, G. H.; Hoivik, N.; Wang, X. M.; Lu, S. S.; Wang, K. Y.; Jakobsen, H. Photoconductive, free-standing crystallized TiO2 nanotube membranes. Electrochim. Acta 2013, 93, 80–86.CrossRefGoogle Scholar
  77. [77]
    Zhao, Y.; Hoivik, N.; Wang, K. Y. Photoconductivity of Au-coated TiO2 nanotube arrays. In Proceedings of the 14th IEEE International Conference on Nanotechnology, Toronto, 2014, pp 180–183.CrossRefGoogle Scholar
  78. [78]
    Bahnemann, D. W.; Hilgendorff, M.; Memming, R. Charge carrier dynamics at TiO2 particles: Reactivity of free and trapped holes. J. Phys. Chem. B 1997, 101, 4265–4275.CrossRefGoogle Scholar
  79. [79]
    Tamaki, Y.; Furube, A.; Murai, M.; Hara, K.; Katoh, R.; Tachiya, M. Direct observation of reactive trapped holes in TiO2 undergoing photocatalytic oxidation of adsorbed alcohols: Evaluation of the reaction rates and yields. J. Am. Chem. Soc. 2006, 128, 416–417.CrossRefGoogle Scholar
  80. [80]
    Xi, G. C.; Ouyang, S. X.; Li, P.; Ye, J. H.; Ma, Q.; Su, N.; Bai, H.; Wang, C. Ultrathin W18O49 nanowires with diameters below 1 nm: Synthesis, near-infrared absorption, photoluminescence, and photochemical reduction of carbon dioxide. Angew. Chem., Int. Ed. 2012, 51, 2395–2399.CrossRefGoogle Scholar
  81. [81]
    Li, Y.; Wang, W.-N.; Zhan, Z. L.; Woo, M.-H.; Wu, C.-Y.; Biswas, P. Photocatalytic reduction of CO2 with H2O on mesoporous silica supported Cu/TiO2 catalysts. Appl. Catal. B: Environ. 2010, 100, 386–392.CrossRefGoogle Scholar
  82. [82]
    Yang, C.-C.; Yu, Y.-H.; van der Linden, B.; Wu, J. C. S.; Mul, G. Artificial photosynthesis over crystalline TiO2-based catalysts: Fact or fiction? J. Am. Chem. Soc. 2010, 132, 8398–8406.CrossRefGoogle Scholar
  83. [83]
    Liu, D.; Fernández, Y.; Ola, O.; Mackintosh, S.; Maroto-Valer, M.; Parlett, C. M. A.; Lee, A. F.; Wu, J. C. S. On the impact of Cu dispersion on CO2 photoreduction over Cu/TiO2. Catal. Commun. 2012, 25, 78–82.CrossRefGoogle Scholar

Copyright information

© Tsinghua University Press and Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  1. 1.Department of Electrical and Computer EngineeringUniversity of AlbertaEdmontonCanada
  2. 2.Department of Chemical & Materials EngineeringUniversity of AlbertaEdmontonCanada
  3. 3.NRC National Institute for NanotechnologyEdmontonCanada

Personalised recommendations