Morris and Egdell reported on a resistive bulk-type sensor of small V2O5-TiO2 bars with Pt electrodes [10]. In contrast, choose size in our study, we realized a planar setup for our resistive sensors and VWT with a V2O5 concentration of 1.5 wt% and 3.0 wt% served as the sensitive functional material. We varied the electrode materials between Pt and Au and measured the resistance changes when Inhibitors,Modulators,Libraries exposed to SO2 and/or other gases. Unexpectedly, it was found out that for the SO2 response the electrode materials play a more crucial role than the vanadium concentration. Furthermore, we discuss the sensing mechanism in this study. It should be noted here that the major objective of this study is to investigate whether commercially available and proven long-term stable SCR catalyst materials are suitable as materials for resistive SO2 sensors.
Material development is not a subject of this study.2.?ExperimentalTypical alumina substrates for thick-film technique (96% Al2O3) were prepared. On the front side of the alumina substrate, Pt or Au interdigital electrodes with a line and space definition of 100 ��m were screen-printed and fired, and a platinum heater was screen-printed on the reverse side Inhibitors,Modulators,Libraries and fired. Then, the sensor layers were fabricated. V2O5/WO3/TiO2 (VWT) was used as a sensing material. VWT powders were supplied by Argillon GmbH. The V2O5 concentration was 1.5 or 3.0 wt% and the WO3 concentration was ca. 8�C10 wt%. In this study, x%VWT is an abbreviation that stands for the composition x wt% V2O5/8�C10 wt% WO3/TiO2, in which x is 1.5 or 3.0.
The VWT powders were mixed with an organic binder to prepare pastes suitable for screen-printing. Afterwards, the pastes were screen-printed on the alumina substrates with the Inhibitors,Modulators,Libraries electrodes and fired at 700 ��C for 20 min. The VWT powder or layer was characterized by scanning electron microscopy (SEM, Leo1450VP), powder X-ray diffraction (PANalytical X��Pert Pro, Cu K�� radiation), and contact probe profilometer (MarSurf). The thickness of VWT layers is in the range of 10�C15 ��m.The sensors were heated by the heater on the reverse side when the sensing properties were determined. The temperature was controlled by utilizing the relationship between heater resistance (as determined in four-wire-technique) and temperature, which had been investigated before using an infrared pyrometer.
By this method, the sensing Inhibitors,Modulators,Libraries element is heated correctly without the influence of gas flow ratio.To investigate its sensing properties, the sensor devices were placed into a Drug_discovery test chamber with an angle of incidence parallel www.selleckchem.com/products/DAPT-GSI-IX.html to the gas flow. The resistance between the electrodes (i.e., the sensor output), was measured by a two-wire-method with a digital multimeter (Keithley 2700 series). The total gas flow amounted to either 1 or 5 L/min. We confirmed that the sensor resistance in base gas was independent of the total gas flow rate.