Solid-state potentiometric SO2 sensor combining NASICON with V2O5-doped TiO2 electrode

Abstract A compact tubular sensor based on NASICON (sodium super ionic conductor) and V2O5-doped TiO2 sensing electrode was designed for the detection of SO2. In order to reduce the size of the sensor, a thick-film of NASICON was formed on the outer surface of a small Al2O3 tube; furthermore, a thin layer of V2O5-doped TiO2 with nanometer size was attached on the NASICON as a sensing electrode. This paper investigated the influence of V2O5 doping and sintering temperature on the characteristics of the sensor. The sensor attached with 5 wt% V2O5-doped TiO2 sintered at 600 °C exhibited excellent sensing properties to 1–50 ppm SO2 in air at 200–400 °C. The EMF value of the sensor was almost proportional to the logarithm of SO2 concentration and the sensitivity (slope) was −78 mV/decade at 300 °C. It was also seen that the sensor showed a good selectivity to SO2 against NO, NO2, CH4, CO, NH3 and CO2. Moreover, the sensor had speedy response kinetics to SO2 too, the 90% response time to 50 ppm SO2 was 10 s, and the recovery time was 35 s. On the basis of XPS analysis for the SO2-adsorbed sensing electrode, a sensing mechanism involving the mixed potential at the sensing electrode was proposed.

[1]  Norio Miura,et al.  High-temperature sensors for NO and NO2 based onstabilized zirconiaand spinel-type oxide electrodes , 1997 .

[2]  L. Wang,et al.  A SO2 gas sensor based upon composite Nasicon/Sr-β-Al2O3 bielectrolyte , 2005 .

[3]  Shaoli Liu,et al.  Solid-electrolyte NASICON thick film CO2 sensor prepared on small-volume ceramic tube substrate , 2005 .

[4]  Norio Miura,et al.  High-temperature hydrogen sensor based on stabilized zirconia and a metal oxide electrode , 1996 .

[5]  W. L. Worrell,et al.  A new sulphur dioxide sensor using a novel two-phase solid-sulphate electrolyte , 1984 .

[6]  C. Liu,et al.  Development of a NASICON-based amperometric carbon dioxide sensor , 2000 .

[7]  Soon-Don Choi,et al.  SO2-sensing characteristics of Nasicon sensors with Na2SO4–BaSO4 auxiliary electrolytes , 2003 .

[8]  N. Yamashita,et al.  Solid electrolyte CO2 sensor using NASICON and perovskite-type oxide electrode , 2000 .

[9]  Fengmin Liu,et al.  Solid-state potentiometric H2S sensor combining NASICON with Pr6O11-doped SnO2 electrode , 2007 .

[10]  Norio Miura,et al.  Characteristics and sensing mechanism of SOx sensor using stabilized zirconia and metal sulphate , 1993 .

[11]  K. Jacob,et al.  An SOx (x = 2, 3) sensor using β-alumina/Na2SO4 couple , 1989 .

[12]  Toshio Maruyama,et al.  Potentiometric sensor for sulfur oxides using nasicon as a solid electrolyte , 1985 .

[13]  Y. Dobrovolsky,et al.  Chemisorption and electrochemical reactions of SO2 on modified SnO2 electrodes , 2005 .

[14]  N. Yamazoe,et al.  NASICON thick film-based CO2 sensor prepared by a sol–gel method , 2001 .

[15]  Duk-Dong Lee,et al.  Carbon dioxide sensor using NASICON prepared by the sol-gel method , 1995 .

[16]  Xiaotian Yang,et al.  Investigation of CO2 sensor based on NASICON synthesized by a new sol–gel process , 2003 .

[17]  Hui Li,et al.  A novel nano-Au-assembled amperometric SO2 gas sensor: preparation, characterization and sensing behavior , 2002 .

[18]  Xiaotian Yang,et al.  Preparation of planar CO2 sensor based on solid-electrolyte NASICON synthesized by sol–gel process , 2004 .

[19]  Hiroyuki Suzuki,et al.  Solid-state NOx sensor combined with NASICON and Pb–Ru-based pyrochlore-type oxide electrode , 2000 .

[20]  S. Wakabayashi,et al.  SO2 gas sensor utilizing stabilized zirconia and sulfate salts with a new working mechanism , 1999 .

[21]  A. Chambaudet,et al.  Modelling of SO2 detection by tin dioxide gas sensors , 1997 .

[22]  Ling Wang,et al.  A new SO2 gas sensor based on an Mg2+ conducting solid electrolyte , 2003 .

[23]  Weiyou Chen,et al.  Preparation and characterization of NASICON with a new sol–gel process , 2004 .