Document Type: Short Review Article


1 Department of Physics, College of Science, University of Anbar, Ramadi, Iraq

2 Department of Chemistry, College of Science, Al-Nahrain University, Al-Jaderia, Baghdad, Iraq



Titanium dioxide is an important metal oxide semiconductor (MOSs) used in many electronic applications, the most famous of which are gas sensor applications. This review discusses the techniques used for preparing the TiO2 thin films and the effect of the crystalline phases in which this compound forms, on the gas sensing properties. There are three phases to crystallize titanium dioxides, brookite, anatase, and rutile phase. Amongst these varied phases of crystal, the greatest steady main phase is rutile. The phase of anatase and brookite are usually more stable than the rutile phase as the surface energy of them is less than that of the rutile. Therefore, the applications of sensing by anatase TiO2 and rutile TiO2 were fully studied. TiO2 characterizations were established on surface reactions using oxidizing or reducing gases, which; therefore, influences the conductivity of the film. Titanium dioxide gas sensors have healthier steadiness and sensitivity at high temperature compared with that of the other metal oxides. Surveys on titanium dioxide thin film applied in gas sensor devices used in a varied range of applications such as sensor devices, dye-sensitized solar cells, and catalysis. The gas sensor is a function of the crystal structure, particle size, morphology, and the method of synthesis. In this work, characteristic of the titanium dioxide films investigated using various techniques, as reported by many researchers. The aim of this study was to review previous studies through which the best properties can obtained to manufacture TiO2 gas sensor thin films with high sensitivity.

Graphical Abstract


[1] Ruiz, A. M., Sakai, G., Cornet, A., Shimanoe, K., Morante, J. R., & Yamazoe, N. (2003). Cr-doped TiO2 gas sensor for exhaust NO2 monitoring. Sensors and Actuators B: Chemical93(1-3), 509-518.

[2] Kim, I., & Choi, W. Y. (2017). Hybrid gas sensor having TiO2 nanotube arrays and SnO2 nanoparticles. International Journal of Nanotechnology14(1-6), 155-165.

[3] Karunagaran, B., Uthirakumar, P., Chung, S. J., Velumani, S., & Suh, E. K. (2007). TiO2 thin film gas sensor for monitoring ammonia. Materials Characterization58(8-9), 680-684.

[4] Kim, W. T., Kim, I. H., & Choi, W. Y. (2015). Fabrication of TiO2 nanotube arrays and their application to a gas sensor. Journal of nanoscience and nanotechnology15(10), 8161-8165.

[5] Vinodhkumar, G., Ramya, R., Potheher, I., & Cyrac Peter, A. (2018). Reduced graphene oxide based on simultaneous detection of neurotransmitters. Progress in Chemical and Biochemical Research1(1, pp. 1-59), 40-49.

[6] Gulati, K., Maher, S., Chandrasekaran, S., Findlay, D. M., & Losic, D. (2016). Conversion of titania (TiO 2) into conductive titanium (Ti) nanotube arrays for combined drug-delivery and electrical stimulation therapy. Journal of Materials Chemistry B4(3), 371-375.

[7] Alkherraz, A., Hashad, O., & Elsherif, K. (2019). Heavy metals contents in some commercially available coffee, tea, and cocoa samples in misurata City–Libya. Progress in Chemical and Biochemical Research2(3), 99-107.

[8] Eldefrawy, M., Gomaa, E. G. A., Salem, S., & Abdel Razik, F. (2018). Cyclic Voltammetric studies of calcium acetate salt with Methylene blue (MB) Using Gold Electrode. Progress in Chemical and Biochemical Research1(1), 11-18..

[9] Zad, Z. R., Davarani, S. S. H., Taheri, A., & Bide, Y. (2018). A yolk shell Fe3O4@ PA-Ni@ Pd/Chitosan nanocomposite-modified carbon ionic liquid electrode as a new sensor for the sensitive determination of fluconazole in pharmaceutical preparations and biological fluids. Journal of Molecular Liquids253, 233-240.

[10] Asif, M., & Mohd, I. (2019). Synthetic methods and pharmacological potential of some cinnamic acid analogues particularly against convulsions. Progress in Chemical and Biochemical Research2(4), 192-210.

[11] Babaei, A., & Taheri, A. (2012). Direct electrochemistry and electrocatalysis of myoglobin immobilized on a novel chitosan-nickel hydroxide nanoparticles-carbon nanotubes biocomposite modified glassy carbon electrode. Anal. Bioanal. Electrochem4(4), 342-356.

[12] Seekaew, Y., Wisitsoraat, A., Phokharatkul, D., & Wongchoosuk, C. (2019). Room temperature toluene gas sensor based on TiO2 nanoparticles decorated 3D graphene-carbon nanotube nanostructures. Sensors and Actuators B: Chemical279, 69-78.

[13] Joo, S., Muto, I., & Hara, N. (2010). Hydrogen gas sensor using Pt-and Pd-added anodic TiO2 nanotube films. Journal of the Electrochemical Society157(6), J221-J226..

[14] Moon, H. G., Shim, Y. S., Su, D., Park, H. H., Yoon, S. J., & Jang, H. W. (2011). Embossed TiO2 thin films with tailored links between hollow hemispheres: synthesis and gas-sensing properties. The Journal of Physical Chemistry C115(20), 9993-9999.

[15] Lou, Z., Li, F., Deng, J., Wang, L., & Zhang, T. (2013). Branch-like hierarchical heterostructure (α-Fe2O3/TiO2): a novel sensing material for trimethylamine gas sensor. ACS applied materials & interfaces5(23), 12310-12316.

[16] Bharathi, J. J., & Pappayee, N. (2014). Titanium dioxide (TiO2) thin film based gas sensors. J. Chem. Pharm. Sci4, 59-61.

[17] Park, J. Y., Choi, S. W., Lee, J. W., Lee, C., & Kim, S. S. (2009). Synthesis and gas sensing properties of TiO2–ZnO core‐shell nanofibers. Journal of the American Ceramic Society92(11), 2551-2554.

[18] Lin, S., Li, D., Wu, J., Li, X., & Akbar, S. A. (2011). A selective room temperature formaldehyde gas sensor using TiO2 nanotube arrays. Sensors and Actuators B: Chemical156(2), 505-509.

[19] Raghu, A. V., Karuppanan, K. K., & Pullithadathil, B. (2018). Highly Sensitive, Temperature-Independent Oxygen Gas Sensor Based on Anatase TiO2 Nanoparticle Grafted, 2D Mixed Valent VO x Nanoflakelets. ACS sensors3(9), 1811-1821.

[20] Tang, H., Prasad, K., Sanjines, R., & Levy, F. (1995). TiO2 anatase thin films as gas sensors. Sensors and Actuators B: Chemical26(1-3), 71-75.

[21] Tai, H., Jiang, Y., Xie, G., Yu, J., Chen, X., & Ying, Z. (2008). Influence of polymerization temperature on NH3 response of PANI/TiO2 thin film gas sensor. Sensors and Actuators B: Chemical129(1), 319-326.

[22] Barreca, D., Carraro, G., Comini, E., Gasparotto, A., Maccato, C., Sada, C., ... & Tondello, E. (2011). Novel synthesis and gas sensing performances of CuO–TiO2 nanocomposites functionalized with Au nanoparticles. The Journal of Physical Chemistry C115(21), 10510-10517.

[23] Jamal M. Rzaij, I. M. Ali, and I. M. Ibrahim. (2016). Effect of Ce doped on the structural , optical , electrical and sensing properties of V2O5 thin films prepared by chemical spray pyrolysis. Global Journal of Engineering Science and Researches, 3(1), 26–38.

[24] Wang, C., Yin, L., Zhang, L., Xiang, D., & Gao, R. (2010). Metal oxide gas sensors: sensitivity and influencing factors. Sensors10(3), 2088-2106.

[25] Seiyama, T., Kato, A., Fujiishi, K., & Nagatani, M. (1962). A new detector for gaseous components using semiconductive thin films. Analytical Chemistry34(11), 1502-1503.

[26] Taguchi, N. (1971). U.S. Patent No. 3,631,436. Washington, DC: U.S. Patent and Trademark Office.

[27] Henrich, V. E., & Cox, P. A. (1994). The Surface Science of Metal Oxides Cambridge Univ.

[28] Heiland, G. (1954). Zum Einfluss von Wasserstoff auf die elektrische Leitfähigkeit von ZnO-Kristallen. Z Phys 138: 459–464.

[29] Seiyama, T., Kato, A., Fujiishi, K., & Nagatani, M. (1962). A new detector for gaseous components using semiconductive thin films. Analytical Chemistry34(11), 1502-1503.

[30] Gong, J., Li, Y., Hu, Z., Zhou, Z., & Deng, Y. (2010). Ultrasensitive NH3 gas sensor from polyaniline nanograin enchased TiO2 fibers. The Journal of Physical Chemistry C114(21), 9970-9974.

[31] Zhang, M., Ning, T., Zhang, S., Li, Z., Yuan, Z., & Cao, Q. (2014). Response time and mechanism of Pd modified TiO2 gas sensor. Materials science in semiconductor processing17, 149-154.

[32] Wang, L., Gao, J., Wu, B., Kan, K., Xu, S., Xie, Y., ... & Shi, K. (2015). Designed synthesis of In2O3 beads@ TiO2–In2O3 composite nanofibers for high performance NO2 sensor at room temperature. ACS Applied Materials & Interfaces7(49), 27152-27159.

[33] Ali, I. M., Rzaij, J. M., Abbas, Q. A., Ibrahim, I. M., & Alatta, H. J. (2018). Structural, Optical and Sensing Behavior of Neodymium-Doped Vanadium Pentoxide Thin Films. Iranian Journal of Science and Technology, Transactions A: Science42(4), 2375-2386.

[34] Comert, B., Akin, N., Donmez, M., Saglam, S., & Ozcelik, S. (2016). Titanium dioxide thin films as methane gas sensors. IEEE Sensors Journal16(24), 8890-8896.

[35] Tan, J., Wlodarski, W., Kalantar-Zadeh, K., & Livingston, P. (2006, October). Carbon monoxide gas sensor based on titanium dioxide nanocrystalline with a Langasite substrate. In SENSORS, 2006 IEEE (pp. 228-231). IEEE.

[36] Arrouvel, C., & Parker, S. C. (2020). Investigating Surface Properties and Lithium Diffusion in Brookite-TiO2. Journal of the Brazilian Chemical Society31(1), 51-65.

[37] Wang, Y., Wu, T., Zhou, Y., Meng, C., Zhu, W., & Liu, L. (2017). TiO2-based nanoheterostructures for promoting gas sensitivity performance: designs, developments, and prospects. Sensors17(9), 1971.

[38] Kakuma, Y., Nosaka, A. Y., & Nosaka, Y. (2015). Difference in TiO 2 photocatalytic mechanism between rutile and anatase studied by the detection of active oxygen and surface species in water. Physical Chemistry Chemical Physics17(28), 18691-18698.

[39] Mor, G. K., Carvalho, M. A., Varghese, O. K., Pishko, M. V., & Grimes, C. A. (2004). A room-temperature TiO 2-nanotube hydrogen sensor able to self-clean photoactively from environmental contamination. Journal of Materials Research19(2), 628-634.

[40] Ju, Y., Wang, M., Wang, Y., Wang, S., & Fu, C. (2013). Electrical properties of amorphous titanium oxide thin films for bolometric application. Advances in Condensed Matter Physics2013.

[41] Taurino, A. M., Capone, S., Siciliano, P., Toccoli, T., Boschetti, A., Guerini, L., & Iannotta, S. (2003). Nanostructured TiO2 thin films prepared by supersonic beams and their application in a sensor array for the discrimination of VOC. Sensors and Actuators B: Chemical92(3), 292-302.

[42] Pawar, S. G., Patil, S. L., Chougule, M. A., Raut, B. T., Godase, P. R., Mulik, R. N., ... & Patil, V. B. (2011). New Method for Fabrication of CSA Doped PANi-${rm TiO} _ {2} $ Thin-Film Ammonia Sensor. IEEE Sensors Journal11(11), 2980-2985.

[43] Galatsis, K., Li, Y. X., Wlodarski, W., Comini, E., Faglia, G., & Sberveglieri, G. (2001). Semiconductor MoO3–TiO2 thin film gas sensors. Sensors and Actuators B: Chemical77(1-2), 472-477.

[44] Yadav, B. C., RadheyshyamSabhajeet, S., & Sonker, R. K. (2018). sol gel formed grape like nanostructured titania based liquefied petroleum gas sensor. Journal of Materials Science and Research.1(1), 290-312.

[45] Nataraj, J. R., Bagali, P. Y., Krishna, M., & Vijayakumar, M. N. (2018). Development of Silver Doped Titanium Oxide Thin films for Gas Sensor Applications. Materials Today: Proceedings5(4), 10670-10680.

[46] Xie, T., Sullivan, N., Steffens, K., Wen, B., Liu, G., Debnath, R., ... & Motayed, A. (2015). UV-assisted room-temperature chemiresistive NO2 sensor based on TiO2 thin film. Journal of alloys and compounds653, 255-259.

[47] Şennik, E., Çolak, Z., Kılınç, N., & Öztürk, Z. Z. (2010). Synthesis of highly-ordered TiO2 nanotubes for a hydrogen sensor. International Journal of Hydrogen Energy35(9), 4420-4427.

[48] Zakrzewska, K., & Radecka, M. (2017). TiO2-based nanomaterials for gas sensing—influence of anatase and rutile contributions. Nanoscale research letters12(1), 89.

[49] Wisitsoraat, A., Tuantranont, A., Comini, E., Sberveglieri, G., & Wlodarski, W. (2006, October). Gas-sensing characterization of TiO2-ZnO based thin film. In SENSORS, 2006 IEEE (pp. 964-967). IEEE.

[50] Radecka, M., Łysoń, B., Lubecka, M., Czapla, A., & Zakrzewska, K. (2010). Photocatalytical Decomposition of Contaminants on Thin Film Gas Sensors. Acta Physica Polonica, A.117(2).

[51] Comert, B., Akin, N., Donmez, M., Saglam, S., & Ozcelik, S. (2016). Titanium dioxide thin films as methane gas sensors. IEEE Sensors Journal16(24), 8890-8896.

[52] Demir, M., Barin, Ö., Karaduman, I., Yıldız, D. E., & Acar, S. (2014). Low concentration of CO gas sensor by atomic layer deposition. Journal of Physical Science and Application4(8), 488-492.

[53] Iftimie, N., Luca, D., Lacomi, F., Girtan, M., & Mardare, D. (2009). Gas sensing materials based on Ti O 2 thin films. Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena27(1), 538-541.

[54] Ponce, M. A., Parra, R., Savu, R., Joanni, E., Bueno, P. R., Cilense, M., ... & Castro, M. S. (2009). Impedance spectroscopy analysis of TiO2 thin film gas sensors obtained from water-based anatase colloids. Sensors and Actuators B: Chemical139(2), 447-452.

[55] Patil, L. A., Suryawanshi, D. N., Pathan, I. G., & Patil, D. G. (2014). Nanocrystalline Pt-doped TiO 2 thin films prepared by spray pyrolysis for hydrogen gas detection. Bulletin of Materials Science37(3), 425-432.

[56] Haidry, A., Schlosser, P., Durina, P., Mikula, M., Tomasek, M., Plecenik, T., ... & Zahoran, M. (2011). Hydrogen gas sensors based on nanocrystalline TiO2 thin films. Open Physics9(5), 1351-1356.

[57] Seo, M. H., Yuasa, M., Kida, T., Huh, J. S., Yamazoe, N., & Shimanoe, K. (2009). Detection of organic gases using TiO2 nanotube-based gas sensors. Procedia Chemistry1(1), 192-195.