Pd doped WO 3 fibers were synthesized by electro-spinning. The sol gel method was employed to prepare peroxopolytungstic acid (P-PTA). Palladium chloride and Polyvinyl pyrrolidone (PVP) was dissolved in the sol Pd:WO 3 = 10% molar ratio. The prepared sol was loaded into a syringe connected to a high voltage of 18.3 kV and electrospun fibers were collected on the alumina substrates. Scanning electron microscope (SEM), X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques were used to analyze the crystal structure and chemical composition of the fibers after heat treatment at 500 °C. Resistance-sensing measurements exhibited a sensitivity of about 30 at 500 ppm hydrogen in air, and the response and recovery times were about 20 and 30 s, respectively, at 300 °C. Hydrogen gas sensing mechanism of the sensor was also studied.
References
[1]
Yamaguchi, T.; Kiwa, T.; Tsukada, K.; Yokosawa, K. Oxygen interference mechanism of platinum–FET hydrogen gas sensor. Sens. Actuators A Phys. 2007, 136, 244–248, doi:10.1016/j.sna.2006.11.026.
[2]
Higuchi, T.; Nakagomi, S.; Kokubun, Y. Field effect hydrogen sensor device with simple structure based on GaN. Sens. Actuators B Chem. 2009, 140, 79–85.
[3]
Villatoro, J.; Moreno, D.L.; Monzón-Hernández, D. Optical fiber hydrogen sensor for concentrations below the lower explosive limit. Sens. Actuators B Chem. 2005, 110, 23–27.
[4]
Slaman, M.; Dam, B.; Schreuders, H.; Griessen, R. Optimization of Mg-based fiber optic hydrogen detectors by alloying the catalyst. Int. J. Hydrog. Energy 2008, 33, 1084–1089.
[5]
Nishibori, M.; Shin, W.; Izu, N.; Itoh, T.; Matsubara, I.; Yasuda, S.; Ohtani, S. Robust hydrogen detection system with a thermoelectric hydrogen sensor for hydrogen station application. Int. J. Hydrog. Energy 2009, 34, 2834–2841.
[6]
Huang, H.; Luan, W.; Zhang, J.S.; Qi, Y.S.; Tu, S.T. Thermoelectric hydrogen sensor working at room temperature prepared by bismuth–telluride P–N couples and Pt/g-Al2O3. Sens. Actuators B Chem. 2008, 128, 581–585, doi:10.1016/j.snb.2007.07.060.
[7]
Ito, K.; Kojima, K. Hydrogen detection by Schottky diodes. Int. J. Hydrog. Energy 1982, 7, 495–497, doi:10.1016/0360-3199(82)90107-0.
[8]
Tang, W.M.; Lai, P.T.; Xu, J.P.; Chan, C.L. Enhanced hydrogen sensing characteristics of MI SiC Schottky-diode hydrogen sensor by trichloroethylene oxidation. Sens. Actuators A Phys. 2005, 119, 63–67, doi:10.1016/j.sna.2004.08.032.
[9]
Tsai, T.H.; Chen, H.I.; Lin, K.W.; Hung, C.W.; Hsu, C.H.; Chen, L.Y.; Chu, K.-Y.; Liu, W.-C. Comprehensive study on hydrogen sensing properties of a Pd–AlGaN-based Schottky diode. Int. J. Hydrog. Energy 2008, 33, 2986–2992.
[10]
Ippolito, S.J.; Kandasamy, S.; Kalantar-Zadeh, K.; Wlodarski, W. Layered SAW hydrogen sensor with modified tungsten trioxide selective layer. Sens. Actuators B Chem. 2005, 108, 553–557.
[11]
Jakubik, W.P. Investigations of thin film structures of WO3 and WO3 with Pd for hydrogen detection in a surface acoustic wave sensor system. Thin Solid Films 2007, 515, 8345–8350, doi:10.1016/j.tsf.2007.03.024.
[12]
Comini, E. Metal oxide nano-crystals for gas sensing. Anal. Chim. Acta 2006, 568, 28–40, doi:10.1016/j.aca.2005.10.069.
[13]
Aroutiounian, V. Metal oxide hydrogen, oxygen, and carbon monoxide sensors for hydrogen setups and cells. Int. J. Hydrog. Energy 2007, 32, 1145–1158, doi:10.1016/j.ijhydene.2007.01.004.
[14]
Adamyana, A.Z.; Adamyana, Z.N.; Aroutiouniana, V.M.; Arakelyana, A.H.; Touryanb, K.J.; Turner, J.A. Sol-gel derived thin film semiconductor hydrogen gas sensor. Int. J. Hydrog. Energy 2007, 32, 4101–4108, doi:10.1016/j.ijhydene.2007.03.043.
[15]
Korotcenkov, G. Metal oxides for solid-state gas sensors: What determines our choice? Mater. Sci. Eng. B 2007, 139, 1–23, doi:10.1016/j.mseb.2007.01.044.
[16]
Adamyan, A.Z.; Adamyan, Z.N.; Aroutiounian, V.M. Study of sensitivity and response kinetics changes for SnO2 thin-film hydrogen sensors. Int. J. Hydrog. Energy 2009, 34, 8438–8443, doi:10.1016/j.ijhydene.2009.08.001.
[17]
Boon-Bretta, L.; Bousek, J.; Morettoa, P. Reliability of commercially available hydrogen sensors for detection of hydrogen at critical concentrations: Part II—Selected sensor test results. Int. J. Hydrog. Energy 2009, 34, 562–571, doi:10.1016/j.ijhydene.2008.10.033.
[18]
Sakai, G.; Matsunaga, N.; Shimanoe, K. Theory of gas-diffusion controlled sensitivity for thin film semiconductor gas sensor. Sens. Actuators B Chem. 2001, 80, 125–131, doi:10.1016/S0925-4005(01)00890-5.
[19]
Eranna, G.; Joshi, B.C.; Runthala, D.P.; Gupta, R.P. Oxide materials for development of integrated gas sensors—A comprehensive review. Crit. Rev. Solid State Mater. Sci. 2004, 29, 111–188, doi:10.1080/10408430490888977.
[20]
Ippolito, S.J.; Kandasamy, S.; Kalantar-Zadeh, K.; Wlodarski, W. Hydrogen sensing characteristics of WO3 thin film conductometric activated by Pt and Au catalysts. Sens. Actuators B Chem. 2005, 108, 154–158, doi:10.1016/j.snb.2004.11.092.
[21]
Ionescu, R.; Hoel, A.; Granqvist, C.G.; Llobet, E.; Heszler, P. Ethanol and H2S gas detection in air and in reducing and oxidizing ambience: Application of pattern recognition to analyze the output from temperature-modulated nanoparticulate WO3 gas sensors. Sens. Actuators B Chem. 2005, 104, 124–131.
[22]
Penza, M.; Martucci, C.; Cassano, G. NOx gas sensing characteristics of WO3 thin films activated by noble metals (Pd, Pt, Au) layers. Sens. Actuators B Chem. 1998, 50, 52–59.
[23]
Luo, Sh.; Fu, G.; Chen, H. Gas-sensing properties and complex impedance analysis of Ce-added WO3 nanoparticles to VOC gases. Solid-State Electron. 2007, 51, 913–919, doi:10.1016/j.sse.2007.04.010.
[24]
Veith, G.M.; Lupini, A.R. Magnetron sputtering of gold nanoparticles onto WO3 and activated carbon. Catal. Today 2007, 122, 248–253.
[25]
Cabot, A.; Arbiol, J.; Morante, J.R. Analysis of the noble metal catalytic additives introduced by impregnation of as obtained SnO2 sol-gel nanocrystals for gas sensors. Sens. Actuators B Chem. 2000, 70, 87–100.
[26]
Opara, U.; Ovec, K.; Orel, B.; Georg, A.; Wittwer, V. The gasochromic properties of sol-gel WO3 films with sputtered Pt catalyst. Pergamon 2000, 68, 541–551.
[27]
Ruiz, A.; Arbiol, J.; Cirera, A.; Cornet, A.; Morante, J.R. Surface activation by Pt-nanoclusters on titania for gas sensing applications. Mater. Sci. Eng. C 2002, 19, 105–109.
[28]
Moreno, D.L.; Monzón-Hernández, D. Effect of the Pd–Au thin film thickness uniformity on the performance of an optical fiber hydrogen sensor. Appl. Surf. Sci. 2007, 253, 8615–8619, doi:10.1016/j.apsusc.2007.04.059.
[29]
Fardindoost, S.; Iraji zad, A.; Rahimi, F.; Ghasempour, R. Pd doped WO3 films prepared by sol-gel process for hydrogen sensing. Int. J. Hydrog. Energy 2010, 35, 854–860.
[30]
Epifani, M.; Abriol, J.; Pellicer, E.; Comini, E.; Siciliano, P.; Faglia, G.; Morante, J.R. Synthesis and gas sensing properties of Pd-Doped SnO2 nanocrystals. A case study of general morphology for doping metal oxides nanocrystals. Cryst. Growth Des. 2008, 8, 1774–1778, doi:10.1021/cg700970d.
[31]
Malyshev, V.V.; Pislyakov, A.V. Investigation of gas-sensitivity of sensor structures to hydrogen in a wide range of temperature, concentration and humidity of gas medium. Sens. Actuators B Chem. 2008, 134, 913–921, doi:10.1016/j.snb.2008.06.046.
[32]
Huang, Z.M.; Zhang, Y.Z.; Kotaki, M.; Ramakrishna, S. A review on polymer nanofibers by electrospinning and their applications in nanocomposites. Compos. Sci. Technol. 2003, 63, 2223–2253, doi:10.1016/S0266-3538(03)00178-7.
[33]
Wang, Z.; Liu, L. Synthesis and ethanol sensing properties of Fe-doped SnO2 nanofibers. Mater. Lett. 2009, 63, 917–919, doi:10.1016/j.matlet.2009.01.051.
[34]
Song, X.; Liu, L. Characterization of electrospun ZnO–SnO2 nanofibers for ethanol sensor. Sens. Actuators A 2009, 154, 175–179.
[35]
Song, X.; Zhang, D.; Fan, M. A novel toluene sensor based on ZnO-SnO2 nanofiber. Appl. Surf. Sci. 2009, 255, 7343–7347, doi:10.1016/j.apsusc.2009.02.094.
[36]
Park, J.A.; Moon, J.; Lee, S.J.; Lim, S.C.; Zyung, T. Fabrication and characterization of ZnO nanofibers by electrospinning. Curr. Appl. Phys. 2009, 9, S210–S212, doi:10.1016/j.cap.2009.01.044.
[37]
Liu, L.; Zhang, T.; Li, S.; Wang, L.; Tian, Y. Preparation, characterization, and gas-sensing properties of Pd-doped In2O3 nanofibers. Mater. Lett. 2009, 63, 1975–1977.
[38]
Zhang, H.; Li, Z.; Liu, L.; Wang, C.; Wei, Y.; MacDiarmid, G.A. Mg2+/Na+-doped rutile TiO2 nanofiber mats for high-speed and anti-fogged humidity sensors. Talanta. 2009, 79, 953–958, doi:10.1016/j.talanta.2009.05.035.
[39]
Wang, Y.; Ramos, I.; Santiago-Avilés, J.J. Detection of moisture and methanol gas using a single electrospun tin oxide nanofiber. IEEE Sensors J. 2007, 7, 1347–1348.
[40]
Lu, X.; Liu, X.; Zhang, W.; Wang, C.; Wei, Y. Large-scale synthesis of tungsten oxide nanofibers by electrospinning. J. Colloid Interface Sci. 2006, 298, 996–999.
[41]
Wang, G.; Ji, Y.; Huang, X.; Yang, X.; Gouma, P.I.; Dudley, M. Fabrication and characterization of polycrystalline WO3 nanofibers and their application for ammonia sensing. J. Phys. Chem. B 2006, 110, 23777–23782.
[42]
Piperno, S.; Passacantando, M.; Santucci, S.; Lozzi, L.; La Rosa, S. WO3 nanofibers for gas sensing applications. J. Appl. Phys. 2007, 101, 124504–124507, doi:10.1063/1.2748627.
[43]
Kudo, T.; Okamoto, H.; Matsumoto, K.; Sasaki, Y. Peroxopolytungstic acids synthesized by direct reaction of tungsten or tungsten carbide with hydrogen peroxide. Inorg. Chim. Acta 1986, 111, L27–L28, doi:10.1016/S0020-1693(00)84626-5.
[44]
Choi, S.-W.; Park, J.Y.; Kim, S.S. Dependence of gas sensing properties in ZnO nanofibers on size and crystallinity of nanograins. J. Mater. Res. 2011, 26, 1662–1665, doi:10.1557/jmr.2011.209.
[45]
Choi, S.-W.; Park, J.Y.; Kim, S.S. Growth behavior and sensing properties of nanograins in CuO nanofibers. Chem. Eng. J. 2011, 172, 550–556, doi:10.1016/j.cej.2011.05.100.
[46]
Park, J.Y.; Asokan, K.M.; Choi, S.-W.; Kim, S.S. Growth kinetics of nanograins in SnO2 fibers and size dependent sensing properties. Sens. Actuators B Chem. 2011, 152, 254–260, doi:10.1016/j.snb.2010.12.017.
[47]
Arbiol, J. Metal Additives Distribution in TiO2 and SnO2 Semiconductor Gas Sensor Nanostructured MaterialsPh.D. Thesis, Barcelona University, Barcelona, Spain, July 2001.
