TiO2 Nanotube Arrays: Application to Hydrogen Sensing



In this chapter we consider application of TiO2 nanotube arrays to hydrogen gas sensing. Hydrogen, a combustible, widely used industrial gas has great potential for use as a carbon-free chemical fuel. The use of hydrogen, or where hydrogen is an undesired contaminant, requires a monitor suitable for detection of meaningful concentrations. Furthermore, quantification of ppm – ppb hydrogen gas concentrations has medical relevance as an indicator of lactose intolerance [1–3], fructose malabsorption [4–8], microbial activity [9], bacterial growth [10–12], fibromyalgia [13], diabetic gastroparesis [14–16], and neonatal necrotizing enterocolitis (NEC) [17–21]. The pathogenesis of neonatal NEC results in the production of hydrogen gas, which accumulates as bubbles in the sub-mucosal area of the bowel wall [18]. Hydrogen is absorbed into the blood stream and excreted transcutaneously, as well as via the lungs into the exhaled breathe [19–21]. For monitoring of NEC in pre-term infants, it appears a clinically useful hydrogen sensor must be capable of detecting transcutaneous hydrogen at levels of approximately 25 ppm to 1 ppm, while the sensitivity of the infants’ skin requires the use of unheated sensors.


Lactose Intolerance Space Charge Layer Sensor Resistance Hydrogen Sensor Hydrogen Exposure 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. 1.
    Rizkalla SW, Luo J, Kabir M, Chevalier A, Pacher N, Slama G (2000) Chronic consumption of fresh but not heated yogurt improves breath-hydrogen status and short-chain fatty acid profiles: A controlled study in healthy men with or without lactose maldigestion. Am J Clin Nutr 72:1474–1479Google Scholar
  2. 2.
    Chong SKF, Ramadan AB, Livesey E, Wood G (2002) The use of a portable breath hydrogen analyser in screening for lactose intolerance in paediatric patients with chronic abdominal pain or chronic diarrhoea. Gastroenterology 122:A363–A363Google Scholar
  3. 3.
    Kanabar D, Randhawa M, Clayton P (2001) Improvement of symptoms in infant colic following reduction of lactose load with lactase. J Hum Nutr Diet 14:359–363CrossRefGoogle Scholar
  4. 4.
    Li DY, Barnes Y, Cuffari C (2002) Who should request a breath hydrogen test? A five-year feasibility, sensitivity of clinical suspicion and cost-effectiveness analysis. Gastroenterology 122:A574–A574CrossRefGoogle Scholar
  5. 5.
    Duro D, Rising R, Cedillo M, Lifshitz E (2002) Association between infantile colic and carbohydrate malabsorption from fruit juices in infancy. Pediatr Res 109:797–805Google Scholar
  6. 6.
    Moukarzel AA, Lesicka H, Ament ME (2002) Irritable bowel syndrome and nonspecific diarrhea in infancy and childhood – Relationship with juice carbohydrate malabsorption. Clin Pediatr 41:145–150CrossRefGoogle Scholar
  7. 7.
    Lebenthal-Bendor Y, Theuer R, Lebenthal A, Tabi I, Lebenthal E (2001) Malabsorption of modified food starch (acetylated distarch phosphate) in normal infants and in 8–24-month-old toddlers with non-specific diarrhea, as influenced by sorbitol and fructose. Acta Paediatr 90:1368–1372CrossRefGoogle Scholar
  8. 8.
    Ledochowski M, Widner B, Murr C, Sperner-Unterweger B, Fuchs D (2001) Fructose malabsorption is associated with decreased plasma tryptophan. Scand J Gastroenterol 4:367–371CrossRefGoogle Scholar
  9. 9.
    Backus RC, Puryear LM, Crouse BA, Biourge VC, Rogers QR (2002) Breath hydrogen concentrations of cats given commercial canned and extruded diets indicate gastrointestinal microbial activity vary with diet type. J Nutr 6:1763S–1766SGoogle Scholar
  10. 10.
    Riordan SM, McIver CJ, Duncombe VM, Thomas MC, Bolin TD (2000) Evaluation of the rice breath hydrogen test for small intestinal bacterial overgrowth. Am J Gastroenterol 95:2858–2864CrossRefGoogle Scholar
  11. 11.
    Bauer TM, Schwacha H, Steinbruckner B, Brinkmann FE, Ditzen AK, Kist M, Blum HE (2000) Diagnosis of small intestinal bacterial overgrowth in patients with cirrhosis of the liver: Poor performance of the glucose breath hydrogen test. J Hepatol 33:382–386CrossRefGoogle Scholar
  12. 12.
    Funayama Y, Sasaki I, Naito H, Fukushima K, Shibata C, Masuko T, Takahashi K, Ogawa H, Sato S, Ueno T, Noguchi M, Hiwatashi N, Matsuno S (1999) Monitoring and antibacterial treatment for postoperative bacterial overgrowth in Crohn’s disease. Dis Colon Rectum 42:1072–1077CrossRefGoogle Scholar
  13. 13.
    Pimentel M, Chow EJ, Lin HC (2000) Comparison of peak breath hydrogen production in patients with irritable bowel syndrome, chronic fatigue syndrome and fibromyalgia. Gastroenterology 118:A413–A413Google Scholar
  14. 14.
    Burge MR, Tuttle MS, Violett JL, Stephenson CL, Schade DS (2000) Breath hydrogen testing identifies patients with diabetic gastroparesis. Diabetes Care 23:860–861CrossRefGoogle Scholar
  15. 15.
    Chiloiro M, Darconza G, Piccioli E, De Carne M, Clemente C, Riezzo G (2001) Gastric emptying and orocecal transit time in pregnancy. J Gastroenterol 36:538–543CrossRefGoogle Scholar
  16. 16.
    Stordal K, Nygaard EA, Bentsen B (2001) Organic abnormalities in recurrent abdominal pain in children. Acta Paediatr 90:638–642CrossRefGoogle Scholar
  17. 17.
    Bisquera JA, Cooper TR, Berseth CL (2002) Impact of necrotizing enterocolitis on length of stay and hospital charges in very low birth weight infants. Pediatrics 109:423–428CrossRefGoogle Scholar
  18. 18.
    Engel RR, Virnig NL (1973) Origin of mural gas in necrotizing enterocolitis. Pediatr Res 7:292–292Google Scholar
  19. 19.
    Godoy G, Truss C, Philips J, Young M, Coffman K, Cassady G (1986) Breath hydrogen excretion in infants with necrotizing enterocolitis. Pediatr Res 20:A348–A348Google Scholar
  20. 20.
    Garstin WIH, Boston VE (1987) Sequential assay of expired breath hydrogen as a means of predicting necrotizing enterocolitis in susceptible infants. Pediatr Res 22:208–210CrossRefGoogle Scholar
  21. 21.
    Cheu HW, Brown DR, Rowe MI (1989) Breath hydrogen excretion as a screening test for the early diagnosis of necrotizing enterocolitis. Am J Dis Children 143:156–159Google Scholar
  22. 22.
    Varghese OK, Gong D, Paulose M, Ong KG, Dickey EC, Grimes CA (2003) Extreme changes in the electrical resistance of titania nanotubes with hydrogen exposure. Adv Mater 15:624–627CrossRefGoogle Scholar
  23. 23.
    Varghese OK, Gong D, Paulose M, Ong KG, Grimes CA (2003) Hydrogen sensing using titania nanotubes. Sens Actuators B 93:338–344CrossRefGoogle Scholar
  24. 24.
    Gong D, Grimes CA, Varghese CA, Hu W, Singh RS, Chen Z, Dickey EC (2001) Titanium oxide nanotube arrays prepared by anodic oxidation. J Mater Res 16:3331–3334CrossRefGoogle Scholar
  25. 25.
    Varghese OK, Paulose M, Gong D, Grimes CA, Dickey EC (2003) Crystallization and high-temperature structural stability of titanium oxide nanotube arrays. J Mater Res 18:156–165CrossRefGoogle Scholar
  26. 26.
    Mor GK, Varghese OK, Paulose M, Mukherjee N, Grimes CA (2003) Fabrication of tapered, conical-shaped titania nanotubes. J Mater Res 18:2588–2593CrossRefGoogle Scholar
  27. 27.
    Christofides C, Mandelis A (1990) Solid-state sensors for trace hydrogen gas-detection. J Appl Phys 68:R1–R30CrossRefGoogle Scholar
  28. 28.
    Ruths PF, Ashok S, Fonash SJ (1981) A study of Pd-Si MIS schottky-barrier diode hydrogen detector. IEEE Trans Electron Devices 28:1003–1009CrossRefGoogle Scholar
  29. 29.
    Schalwig J, Muller G, Karrer U, Eickhoff M, Ambacher O, Stutzmann M, Gorgens L, Dollinger G (2002) Hydrogen response mechanism of Pt-GaN Schottky diodes. Appl Phys Lett 80:1222–1224CrossRefGoogle Scholar
  30. 30.
    Roy S, Jacob C, Lang C, Basu S (2003) Studies on Ru/3C-SiC Schottky junctions for high temperature hydrogen sensors. J Electrochem Soc 150:H135–H139CrossRefGoogle Scholar
  31. 31.
    Cheng S-Y (2003) A hydrogen sensitive Pd/GaAs Shottky diode sensor. Mater Chem Phys 78:525–528CrossRefGoogle Scholar
  32. 32.
    Butler MA (1991) Fiber optic sensor for hydrogen concentrations near the explosive limit. J Electrochem Soc 138:L46–L47CrossRefGoogle Scholar
  33. 33.
    Sekimoto S, Nakagawa H, Okazaki S, Fukuda K, Asakura S, Shingemori T, Takahashi S (2000) A fiber-optic evanescent-wave hydrogen gas sensor using palladium-supported tungsten oxide. Sens Actuators B 66:142–145CrossRefGoogle Scholar
  34. 34.
    Sutapun B, Tabib-Azar M, Kazemi A (1999) Pd-coated elastooptic fiber optic Bragg grating sensors for multiplexed hydrogen sensing. Sens Actuators B 60:27–34CrossRefGoogle Scholar
  35. 35.
    Matsumiya M, Shin W, Izu N, Murayama N (2003) Nano-structured thin-film Pt catalyst for thermoelectric hydrogen gas sensor. Sens Actuators B 93:309–315CrossRefGoogle Scholar
  36. 36.
    Katti VR, Debnath AK, Gadkari SC, Gupta SK, Sahni VC (2002) Passivated thick film catalytic type H-2 sensor operating at low temperature. Sens Actuators B 84:219–225CrossRefGoogle Scholar
  37. 37.
    Luo RX, Chen LH, Chen AF, Liu CC (1991) A novel catalytic sensor for monitoring the concentration of mixed combustible gases. Sci China A 34:1500–1507Google Scholar
  38. 38.
    Maffei N, Kuriakose AK (1999) A hydrogen sensor based on a hydrogen ion conducting solid electrolyte. Sens Actuators B 56:243–246CrossRefGoogle Scholar
  39. 39.
    Katahira K, Matsumoto H, Iwahara H, Koide K, Iwamoto T (2001) A solid electrolyte hydrogen sensor with an electrochemically-supplied hydrogen standard. Sens Actuators B 73:130–134CrossRefGoogle Scholar
  40. 40.
    Lu G, Miura N, Yamazoe N (1996) High temperature hydrogen sensor based on stabilized zirconia and a metal oxide electrode. Sens Actuators B 35:130–135CrossRefGoogle Scholar
  41. 41.
    Miura N, Harada T, Shimizu Y, Yamazoe N (1990) Cordless solid-state hydrogen sensor using proton-conductor thick film. Sens Actuators B 1:125–129CrossRefGoogle Scholar
  42. 42.
    Lundstroem I, Shivaraman S, Svensson C, Lundkvist L (1975) Hydrogen-sensitive mos field-effect transistor. Appl Phys Lett 26:55–57CrossRefGoogle Scholar
  43. 43.
    Miura N, Harada T, Yoshida N, Shimizu Y, Yamazoe N (1995) Sensing characteristics of ISFET-based hydrogen sensor using proton conductive thick film. Sens Actuators B 25:499–503CrossRefGoogle Scholar
  44. 44.
    Fomenko S, Gumenjuk S, Podlepetsky B, Chuvashov V, Safronkin G (1992) The influence of technological factors on the hydrogen sensitivity of mosfet sensors. Sens Actuators B 10:7–10CrossRefGoogle Scholar
  45. 45.
    Mor GK, Varghese OK, Paulose M, Shankar K, Grimes CA (2006) A review on highly ordered, vertically oriented TiO2 nanotube arrays: Fabrication, material properties, and solar energy applications. Sol Energy Mater Sol Cells 90:2011–2075CrossRefGoogle Scholar
  46. 46.
    Hyodo T, Nishida N, Shimizu Y, Egashira M (2002) Preparation and gas sensing properties of thermally stable mesoporous SnO2. Sens Actuators B 83:209–215CrossRefGoogle Scholar
  47. 47.
    Chaudhary VA, Mulla IS, Vijaymohanan K (1999) Selective hydrogen sensing properties of surface functionalized tin oxide. Sens Actuators B 55:154–160CrossRefGoogle Scholar
  48. 48.
    Fonash SJ, Li Z, Oleary MJ (1985) An extremely sensitive heterostructure for parts per million detection of hydrogen in oxygen. J Appl Phys 58:4415–4419CrossRefGoogle Scholar
  49. 49.
    Reddy CVG, Manorama SV (2000) Room temperature hydrogen sensor based on SnO2:La2O3. J Electrochem Soc 147:390–393CrossRefGoogle Scholar
  50. 50.
    Basu S, Dutta A (1994) Modified heterojunction based on zinc-oxide thin-film for hydrogen gas-sensor application. Sens Actuators B 22:83–87CrossRefGoogle Scholar
  51. 51.
    Nakagawa H, Yamamoto N, Okazaki S, Chinzei T, Asakura S (2003) A room-temperature operated hydrogen leak sensor. Sens Actuators B 93:468–474CrossRefGoogle Scholar
  52. 52.
    Yamamoto N, Tonomura S, Matsuoka T, Tsubomura H (1980) Study on a palladium-titanium oxide schottky diode as a detector for gaseous components. Surf Sci 92:400–406CrossRefGoogle Scholar
  53. 53.
    Mor GK, Varghese OK, Paulose M, Grimes CA (2003) A Self-cleaning Room Temperature Titania-Nanotube Hydrogen Gas Sensor. Sens Lett 1:42–46CrossRefGoogle Scholar
  54. 54.
    Varghese OK, Mor GK, Grimes CA, Paulose M, Mukherjee N (2004) A titania nanotube array room temperature sensor for selective detection of hydrogen at low concentrations. J Nanosci Nanotechnol 4:733–737CrossRefGoogle Scholar
  55. 55.
    Mor GK, Varghese OK, Paulose M, Grimes CA (2006) Fabrication of hydrogen detectors with transparent titanium oxide nanotube array thin films as sensing elements. Thin Solid Films 496:42–48CrossRefGoogle Scholar
  56. 56.
    Huiberts JN, Griessen R, Rector JH, Wijngaarden RJ, Dekker JP, de Groot DG, Koeman NJ (1996) Yttrium and lanthanum hydride films with switchable optical properties. Nature 380:231–234CrossRefGoogle Scholar
  57. 57.
    Pick MA, Davenport JW, Strongin M, Dienes GJ (1979) Enhancement of hydrogen uptake rates for Nb and Ta by thin surface overlayers. Phys Rev Lett 43:286–289CrossRefGoogle Scholar
  58. 58.
    Beydoun D, Amal R, Low G, McEvoy S (1999) Role of nanoparticles in photocatalysis. J Nanopart Res 1:439–458CrossRefGoogle Scholar
  59. 59.
    Mor GK, Carvalho MA, Varghese OK, Pishko MV, Grimes CA (2004) A room-temperature TiO2-nanotube hydrogen sensor able to self-clean photoactively from environmental contamination. J Mater Res 19:628–634CrossRefGoogle Scholar
  60. 60.
    Moseley PT (1992) Materials selection for semiconductor gas sensors. Sens Actuators B 6:149–156CrossRefGoogle Scholar
  61. 61.
    Madou MJ, Morrison SR (1989) Chemical sensing with solid state devices. Academic, New YorkGoogle Scholar
  62. 62.
    Wang CC, Akbar SA, Madou MJ (1998) Ceramic based resistive sensors. J Electroceram 2:273–282CrossRefGoogle Scholar
  63. 63.
    Harrison PG, Willett MJ (1988) The mechanism of operation of tin(iv) oxide carbon-monoxide sensors. Nature 332:337–339CrossRefGoogle Scholar
  64. 64.
    Shimizu Y, Kuwano N, Hyodo T, Egashira M (2002) High H2 sensing performance of anodically oxidized TiO2 film contacted with Pd. Sens Actuators B 83:195–201CrossRefGoogle Scholar
  65. 65.
    Varghese OK, Grimes CA (2004) Metal oxide nanostructures as gas sensors. Encyclopedia of Nanoscience and Nanotechnology. (Ed) Nalwa HS, American Scientific Publishers, Valencia, CA. USA 5:505–521Google Scholar
  66. 66.
    Kolmakov A, Klenov DO, Lilach Y, Stemmer S, Moskovits M (2005) Enhanced gas sensing by individual SnO2 nanowires and nanobelts functionalized with Pd catalyst particles. Nano Lett 5:667–673CrossRefGoogle Scholar
  67. 67.
    Arnold MS, Avouris P, Pan ZW, Wang ZL (2003) Field-effect transistors based on single semiconducting oxide nanobelts. J Phys Chem B 107:659–663CrossRefGoogle Scholar
  68. 68.
    Wu NL, Wang SY, Rusakova IA (1999) Inhibition of crystallite growth in the sol-gel synthesis of nanocrystalline metal oxides. Science 285:1375–1377CrossRefGoogle Scholar
  69. 69.
    Zhang DH, Liu ZQ, Li C, Tang T, Liu XL, Han S, Lei B, Zhou CW (2004) Detection of NO2 down to ppb levels using individual and multiple In2O3 nanowire devices. Nano Lett 4:1919–1924CrossRefGoogle Scholar
  70. 70.
    Comini E, Faglia G, Sberveglieri G, Pan ZW, Wang ZL (2002) Stable and highly sensitive gas sensors based on semiconducting oxide nanobelts. Appl Phys Lett 81:1869–1871CrossRefGoogle Scholar
  71. 71.
    Liu JF, Wang X, Peng Q, Li YD (2005) Vanadium pentoxide nanobelts: Highly selective and stable ethanol sensor materials. Adv Mater 17:764–767CrossRefGoogle Scholar
  72. 72.
    Wan Q, Li QH, Chen YJ, Wang TH, He XL, Li JP, Lin CL (2004) Fabrication and ethanol sensing characteristics of ZnO nanowire gas sensors. Appl Phys Lett 84:3654–3656CrossRefGoogle Scholar
  73. 73.
    Wang SH, Chou TC, Liu CC (2003) Nano-crystalline tungsten oxide NO2 sensor. Sens Actuators B 94:343–351CrossRefGoogle Scholar
  74. 74.
    Wang ZL (2004) Functional oxide nanobelts: Materials, properties and potential applications in nanosystems and biotechnology. Ann Rev Phys Chem 55:159–196CrossRefGoogle Scholar
  75. 75.
    Mor GK, Shankar K, Paulose M, Vaeghese OK, Grimes CA (2005) Enhanced photocleavage of water using titania nanotube arrays. Nano Lett 5:191–195CrossRefGoogle Scholar
  76. 76.
    Varghese OK, Paulose M, Shankar K, Mor GK, Grimes CA (2005) Water-photolysis properties of micron-length highly-ordered titania nanotube-arrays. J Nanosci Nanotechnol 5:1158–1165CrossRefGoogle Scholar
  77. 77.
    Paulose M, Varghese OK, Mor GK, Grimes CA, Ong KG (2006) Unprecedented ultra-high hydrogen gas sensitivity in undoped titania nanotubes. Nanotechnol 17:398–402CrossRefGoogle Scholar
  78. 78.
    Capovilla J, VanCouwenberghe C, Miller WA (2000) Noninvasive blood gas monitoring. Crit Care Nurs Q 23:79–86Google Scholar
  79. 79.
    Varghese OK, Yang X, Kendig J, Paulose M, Zeng K, Palmer C, Ong KG, Grimes CA (2006) A transcutaneous hydrogen sensor: From design to application. Sens Lett 4:120–128CrossRefGoogle Scholar
  80. 80.
    Hammerschmidt DE (2004) Breath hydrogen and lactose intolerance. J Lab Clin Med 144:279–279Google Scholar
  81. 81.
    Pimentel M, Kong Y, Park S (2003) Breath testing to evaluate lactose intolerance in irritable bowel syndrome correlates with lactulose testing and may not reflect true lactose malabsorption. Am J Gastroenterol 98:2700–2704CrossRefGoogle Scholar
  82. 82.
    Adam AC, Rubio-Texeira M, Polaina J (2004) Lactose: The milk sugar from a biotechnological perspective. Crit Rev Food Sci Nutr 44:553–557CrossRefGoogle Scholar
  83. 83.
    Goldberg DM (1987) The enzymology of intestinal disease. Clin Biochem 20:63–72CrossRefGoogle Scholar
  84. 84.
    Cavalli-Sforza LT, Menozzi P, Strata A (1983) A model and program for study of a tolerance curve: Application to lactose absorption tests. Int J Bio-Med Comput 14:31–41CrossRefGoogle Scholar
  85. 85.
    Gerlach P, das Hautathmen U (1851) Arch Anat Physiol 431–479Google Scholar
  86. 86.
    Shannon RD (1964) Phase transformation studies in TiO2 supporting different defect mechanisms in vacuum-reduced + hydrogen-reduced rutile. J Appl Phys 35:3414–3418CrossRefGoogle Scholar
  87. 87.
    Kim KH, Oh EJ, Choi JS (1984) Electrical-conductivity of hydrogen-reduced titanium-dioxide (rutile). J Phys Chem Solids 45:1265–1269CrossRefGoogle Scholar
  88. 88.
    Walton RM, Dwyer DJ, Schwank JW, Gland JL (1998) Gas sensing based on surface oxidation reduction of platinum-titania thin films II. The role of chemisorbed oxygen in film sensitization. Appl Surf Sci 125:199–207CrossRefGoogle Scholar
  89. 89.
    Roland U, Braunschweig T, Roessner F (1997) On the nature of spilt-over hydrogen. J Mol Catal A 127:61–84CrossRefGoogle Scholar
  90. 90.
    Knotek ML (1980) Characterization of hydrogen species on TiO2 by electron-stimulated desorption. Surf Sci 91:L17–L22CrossRefGoogle Scholar
  91. 91.
    Raupp GB, Dumesic JA (1985) Adsorption of CO, CO2, H2, and H2O on titania surfaces with different oxidation-states. J Phys Chem 89:5240–5246CrossRefGoogle Scholar
  92. 92.
    Gopel W, Rocker G, Feierabend R (1983) Intrinsic defects of TiO2 (110) – interaction with chemisorbed O2, H2, CO, and CO2. Phys Rev B 28:3427–3438CrossRefGoogle Scholar
  93. 93.
    Knauth P, Tuller HL (1999) Electrical and defect thermodynamic properties of nanocrystalline titanium dioxide. J Appl Phys 85:897–902CrossRefGoogle Scholar
  94. 94.
    Bodzenta J, Burak B, Gacek Z, Jakubik WP, Kochowski S, Urbanczyk M (2002) Thin palladium film as a sensor of hydrogen gas dissolved in transformer oil. Sens Acuators B 87:82–87CrossRefGoogle Scholar
  95. 95.
    Abdullah M, Low GKC, Matthews RW (1990) Effects of common inorganic anions on rates of photocatalytic oxidation of organic-carbon over illuminated titanium-dioxide. J Phys Chem 94:6820–6825CrossRefGoogle Scholar
  96. 96.
    Zeman P, Takabayashi S (2002) Self-cleaning and antifogging effects of TiO2 films prepared by radio frequency magnetron sputtering. J Vac Sci Tech A 20:388–393CrossRefGoogle Scholar
  97. 97.
    Zheng S, Gao L, Zhang QH, Sun J (2001) Synthesis, characterization, and photoactivity of nanosized palladium clusters deposited on titania-modified mesoporous MCM-41. J Solid State Chem 162:138–141CrossRefGoogle Scholar
  98. 98.
    Wang CM, Heller A, Wang GH, CM HA, Gerischer H (1992) Palladium catalysis of O2 reduction by electrons accumulated on TiO2 particles during photoassisted oxidation of organic-compounds. J Am Chem Soc 114:5230–5234CrossRefGoogle Scholar
  99. 99.
    Papp J, Shen HS, Kershaw R, Dwight K, Wold A (1993) Titanium(iv) oxide photocatalysts with Palladium. Chem Mater 5:284–288CrossRefGoogle Scholar
  100. 100.
    Wang CC, Zhang ZB, Ying JY (1997) Photocatalytic decomposition of halogenated organics over nanocrystalline titania. Nanostruct Mater 9:583–586CrossRefGoogle Scholar
  101. 101.
    Zhang ZB, Wang CC, Zakaria R, Ying JY (1998) Role of particle size in nanocrystalline TiO2-based photocatalysts. J Phys Chem B 102:10871–10878CrossRefGoogle Scholar
  102. 102.
    Basu S, Dutta A (1997) Room-temperature hydrogen sensors based on ZnO. Mater Chem Phys 47:93–96CrossRefGoogle Scholar
  103. 103.
    Zuttel A, Nutzenadel C, Schmid G, Emmenegger C, Sudan P, Schlapbach L (2000) Thermodynamic aspects of the interaction of hydrogen with Pd clusters. Appl Surf Sci 162:571–575CrossRefGoogle Scholar
  104. 104.
    Michaelson HB (1977) Work function of elements and its periodicity. J Appl Phys 48:4729–4733CrossRefGoogle Scholar
  105. 105.
    Henrich VE, Cox PA (1994) The surface science of metal oxides. Cambridge University Press, New YorkGoogle Scholar
  106. 106.
    Huang WX, Zhai RS, Bao XH (2000) Investigation of oxygen adsorption on Pd (100) with defects. Appl Surf Sci 158:287–291CrossRefGoogle Scholar
  107. 107.
    Kobayashi H, Kishimoto K, Nakato Y (1994) Reactions of hydrogen at the interface of palladium titanium-dioxide schottky diodes as hydrogen sensors, studied by work function and electrical characteristic measurements. Surf Sci 306:393–405CrossRefGoogle Scholar
  108. 108.
    Varghese OK, Mor GK, Paulose M, Grimes CA (2005) A titania nanotube-array room-temperature sensor for selective detection of low hydrogen concentrations. Mater Res Soc Symp Proc 835:A3.1.1/K4.1.1Google Scholar
  109. 109.
    Eder D, Kramer R (2003) Stoichiometry of “titanium suboxide” – Part 2 Electric properties. Phys Chem Chem Phys 5:1314–1319CrossRefGoogle Scholar
  110. 110.
    Walton RM, Dwyer DJ, Schwank JW, Gland JL (1998) Gas sensing based on surface oxidation reduction of platinum-titania thin films I. Sensing film activation and characterization. Appl Surf Sci 125:187–198CrossRefGoogle Scholar
  111. 111.
    Birkefeld LD, Azad AM, Akbar SA (1992) Carbon-monoxide and hydrogen detection by anatase modification of titanium-dioxide. J Am Chem Soc 75:2964–2968Google Scholar
  112. 112.
    Madou MJ, Morrison SR (1989) Chemical sensing with solid state devices. Academic, New YorkGoogle Scholar
  113. 113.
    Wang CC, Akbar SA, Madou MJ (1998) Ceramic based resistive sensors. J Electroceram 2:273–282CrossRefGoogle Scholar
  114. 114.
    Bates JB, Wang JC, Perkins RA (1979) Mechanisms for hydrogen diffusion in TiO2. Phys Rev B 19:4130–4139CrossRefGoogle Scholar
  115. 115.
    Roland U, Salzer R, Braunschweig T, Roessner F, Winkler H (1995) Investigations on hydrogen spillover.1. electrical-conductivity studies on titanium-dioxide. J Chem Soc-Faraday Trans 91:1091–1095CrossRefGoogle Scholar
  116. 116.
    Morimoto T, Nagao M, Tokuda F (1969) Relation between amounts of chemisorbed and physisorbed water on metal oxides. J Phys Chem 73:243–248CrossRefGoogle Scholar
  117. 117.
    Ogawa H, Niashikawa M, Abe A (1982) Hall measurement studies and an electrical-conduction model of tin oxide ultrafine particle films. J Appl Phys 53:4448–4455CrossRefGoogle Scholar
  118. 118.
    Bisquera JA, Cooper TR, Berseth CL (2002) Impact of necrotizing enterocolitis on length of stay and hospital charges in very low birth weight infants. Pediatrics 109:423–428CrossRefGoogle Scholar
  119. 119.
    Engel RR, Virnig NL (1973) Origin of mural gas in necrotizing enterocolitis. Pediatr Res 7:292–294Google Scholar

Copyright information

© Springer Science + Business Media, LLC 2009

Authors and Affiliations

  1. 1.Electrical Engineering DepartmentPennsylvania State UniversityUniversity ParkUSA
  2. 2.Materials Research InstitutePennsylvania State UniversityUniversity ParkUSA

Personalised recommendations