Amperometric gas sensor in different orientation towards analyte flow at different flow rates and different concentrations

Published: 21-01-2020| Version 1 | DOI: 10.17632/4jhgxxkkt4.1
Contributors:
Petr Kuberský,
Petr Sedlak

Description

This dataset contains three sets of raw measurement data. The experiments were carried out on three−electrode sensor platform based on ceramic substrate with platinum counter and pseudoreference electrode. Solid polymer electrolyte (SPE) contained [C2mim][NTf2] ionic liquid, PVDF and NMP. Carbon working electrode (WE) was prepared by spray coating a mixture consisting of 300 mg glassy carbon spherical powder and 1 ml of ethanol. More information about the sensors can be found in Ref.[1-2]. All three sets contain the current responses of particular sensors in time domains at conditions specified below. Within the first set of experiments, sensors of three different working electrode areas (2.9, 8.5 and 22.4 mm2) were particularly exposed to the test profile that consisted of a stepwise increase in nitrogen dioxide concentration from 0 to 3 ppm (1 step equaled 1 ppm NO2) with subsequent three consecutive exposures to the same concentration of 3 ppm NO2 . The same test profile was applied to four different total flow rates of analyte (0.1, 0.5, 0.8 and 1 L/min) in order to observe the impact of the flow rate level on sensor parameters (sensitivity, response/recovery time, limit of detection, repeatability) for each size of the working electrode area. Each tested sensor was placed on the same position in the test chamber to be in the most identical conditions. The second set of experiments was carried out on the sensor with the largest WE surface area which was placed in the air and rotated for angles 0°, 45°, 90° and 270° in order to examine the effect of mutual orientation of the WE surface area and analyte flow direction on sensor parameters. The same test profiles of the first experimental sets were applied to a particular angle. The third set of experiments was provided under equilibrium conditions when the sensor with the largest WE surface area was being kept at the particular conditions (concentration and flow rate) for required amount of time to fulfil memorylessness of current fluctuations. These measurements of DC current and its fluctuation were done (i) for a range of concentration at the constant flow rate (1 L/min) and (ii) for a range of flow rates at a constant concentration (NO2 3 ppm). Firstly, a particular NO2 concentration (e.g. 1 ppm) was set with the particular total flow rate (e.g. 1 L/min). The DC current via sensor was monitored until it not changed its mean value for 100 seconds. After this (approximately 300 s from the beginning of the procedure), current fluctuations measurement (CH1) with DC current measurement (CH2) were carried out. Relative humidity and temperature were constant within all experiments (298 K and 40 %RH). The used measurement setups are described in detail in [2,3] as well as in manuscript "Effect of orientation to analyte flow on electrochemical sensor performance and current fluctuations" submitted to journal Sensors, where all evaluations are also described.

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