Electrochemical sensing of gases based on liquid collection interfaces (original) (raw)
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Solid-state electrochemical gas sensors
2006
Various types of solid-state electrochemical gas sensors are presented. The sensing mechanism and examples of potentiometric, amperometric and electrocatalytic sensors are described. The possibility of multi-gas detection in the case of amperometric and electrocatalytic sensors is characterized. The principle of operation of the wide-band oxygen sensor, combining the potentiometric and amperometric modes, is presented. Key words: electrochemical gas sensor; solid electrolyte; air monitoring
Electrochemical solid state gas sensors: An overview
Ionics, 2007
Gas sensors has been currently in great demand because of serious concern over environmental pollution and public health considerations resulting from tremendous growth of industrialisation. Concurrently, there have been continuous efforts to obtain sensors with improved performance. The performance of any solid-state electrochemical gas sensor has been always rated on its response time, thermodynamic stability, operating temperature, gas sensing ability, sensitivity and gas concentration range, which is to be sensed. This article reviews the factors contributing towards a gradual development of electrochemical solidstate gas sensors in terms of a continuous tailoring of its two basic components, i.e. solid electrolyte and reference electrode.
Evaluation of a simple disposable microband electrode device for amperometric gas sensing
Sensors and Actuators B: Chemical, 2013
We report a simple and facile methodology for constructing Pt (6.3 mm × 50 m) and Cu (6.3 mm × 30 m) annular microband electrodes for use in room temperature ionic liquids (RTILs) and propose their use for amperometric gas sensing. The suitability of microband electrodes for use in electrochemical analysis was examined in experiments on two systems. The first system studied to validate the electrochemical responses of the annular microband electrode was decamethylferrocene (DmFc), as a stable internal reference probe commonly used in ionic liquids, in [Pmim][NTf 2 ], where the diffusion coefficients of DmFc and DmFc + and the standard electron rate constant for the DmFc/DmFc + couple were determined through fitting chronoamperometric and cyclic voltammetric responses with relevant simulations. These values are independently compared with those collected from a commercially available Pt microdisc electrode with excellent agreement. The second system focuses on O 2 reduction in [Pmim][NTf 2 ], which is used as a model for gas sensing. The diffusion coefficients of O 2 and O− 2 and the electron transfer rate constant were again obtained using chronoamperometry and cyclic voltammetry, along with simulations. Results determined from the microbands are again consistent to those evaluated from the Pt microdisc electrode when compared these results from home-made microband and commercially available microdisc electrodes. These observations indicate that the fabricated annular microband electrodes are suitable for quantitative measurements. Further the successful use of the Cu electrodes in the O 2 system suggests a cheap disposable sensor for gas detection.
Solid electrolyte gas sensors based on cyclic voltammetry with one active electrode
IOP Conference Series: Materials Science and Engineering, 2011
Solid state gas sensors are cost effective, small, rugged and reliable. Typically electrochemical solid state sensors operate in either potentiometric or amperometric mode. However, a lack of selectivity is sometimes a shortcoming of such sensors. It seems that improvements of selectivity can be obtained in case of the electrocatalytic sensors, which operate in cyclic voltammetry mode. Their working principle is based on acquisition of an electric current, while voltage ramp is applied to the sensor. The current-voltage response depends in a unique way on the type and concentration of ambient gas. Most electrocatalytic sensors have symmetrical structure. They are in a form of pellets with two electrodes placed on their opposite sides. Electrochemical reactions occur simultaneously on both electrodes. In this paper results for sensors with only one active electrode exposed to ambient gas are presented. The other electrode was isolated from ambient gas with dielectric sealing. This sensor construction allows application of advanced measuring procedures, which permit sensor regeneration acceleration. Experiments were conducted on Nasicon sensors. Properties of two sensors, one with one active electrode and second with symmetrical structure, used for the detection of mixtures of NO 2 and synthetic air are compared.
Electrochemical Sensing of Oxygen Gas in Ionic Liquids
The work presented in this thesis aimed to investigate the potentiality of screen printed electrodes (SPEs), when used in conjunction with non-volatile room temperature ionic liquids (RTILs), for the amperometric sensing of gases. O 2 was selected as the model gas for these studies. Cyclic voltammetry (CV) and amperometry techniques were employed for these investigations. Experiments were conducted with an inert background atmosphere of N 2 gas.
IEEE Sensors Journal, 2018
Among gas sensors, the ones measuring carbon dioxide and oxygen are crucial for many application fields: the monitoring of air quality, the control of food packaging processes, the study of biochemical mechanisms, and specific reactions related to many different studies in the biomedical context. Many of the sensors used for the measure of carbon dioxide (CO 2) and oxygen (O 2) are based on electrochemical, optical, and conductometric working principles, which allow to cover the very different ranges of concentration which represent the target of each different field or specific application with good reproducibility and sensitivity. This paper presents a voltammetric sensor showing an innovative approach for the measure of gas and vapors by the interaction of a screen-printed electrode system with the liquid solution, where the gases are conveyed. The design and realization of this sensor system are reported. Calibration tests with CO 2 and O 2 have given acceptable reproducibility and sensitivity. Besides, this paper shows that new results have been obtained by analyzing exhaled breath collected by control individuals.
Highly selective solid electrolyte sensor for the analysis of gaseous mixtures
Journal of Sensors and Sensor Systems
The operation principle of a commercially available solid electrolyte sensor was modified with respect to applications in flowing gaseous mixtures containing H<sub>2</sub> and O<sub>2</sub>. For this purpose the generally applied coulometric or potentiometric operation mode was replaced by cyclic voltammetry. By varying the sensor temperature, electrode area and potential scan rate, the conditions for the characteristic peak formation for every gas component were determined. While hydrogen oxidation peaks arise at potential scan rates up to…
Catalysts, 2021
The rapid development of science, technology, and engineering in the 21st century has offered a remarkable rise in our living standards. However, at the same time, serious environmental issues have emerged, such as acid rain and the greenhouse effect, which are associated with the ever-increasing need for energy consumption, 85% of which comes from fossil fuels combustion. From this combustion process, except for energy, the main greenhouse gases-carbon dioxide and steam-are produced. Moreover, during industrial processes, many hazardous gases are emitted. For this reason, gas-detecting devices, such as electrochemical gas sensors able to analyze the composition of a target atmosphere in real time, are important for further improving our living quality. Such devices can help address environmental issues and inform us about the presence of dangerous gases. Furthermore, as non-renewable energy sources run out, there is a need for energy saving. By analyzing the composition of combusti...
Continuous monitoring of gas-phase species at trace levels with electrochemical detectors
Analytica Chimica Acta, 1991
A detection system suitable for the contmuous and simultaneous measurement of gas-phase chlonne and hydrogen chlonde m the low parts per b&on (10') by volume (ppbv) range 1s described Both gases are trapped through the walls of a microporous polypropylene tube mto an appropriate flowmg recipient buffer. The buffer then flows through two electrochenncal detectors placed m series downstream from the sampling tube. Chlonde ions from gas-phase hydrogen chlonde are detected potentlometncally with an Ag/AgCI working electrode Chlonne IS detected biarnperometncally (at 0 1 V) via its oxidation of added lo&de tons to form ttiodide. In a contmuous-flow measurement mode, detection of chlonne and hydrogen chloride at levels as low as 0.75 and 2.1 ppbv, respectively, 1s possible. Use of a 2-mm stopped-flow/flow-mjectlon arrangement results m a threefold improvement m detectIon linnts The selectlvlty of each detector wth respect to carbon &oxlde, sulfur &oxlde, rutrogen dioxide and hydrogen sulfide 1s also exammed