Use of Room Temperature Ionic Liquids in Gas Sensor Design

Abstract

The attainable steady-state limiting currents and time responses of membrane-covered and membrane-independent gas sensors incorporating different electrode and electrolyte materials have been compared. A new design comprising a membrane-free microelectrode modified with a thin layer of a room temperature ionic liquid is considered. While the use of ionic liquid as electrolyte eliminates the need for a membrane and added supporting electrolyte, the slower diffusion of analyte within the more viscous medium results in slower time responses. Such sensors do, however, have potential application in more extreme operating conditions, such as high temperature and pressure, where traditional solvents would volatise.

The electrochemistry of simple inorganic molecules in room temperature ionic liquids

“…As a result, several researchers have investigated the use of RTILs as electrolytes in gas sensors. 9,32 A practical drawback is that response times are slower due to the much higher viscosity of the RTIL compared to traditional solvents, and their sensitivity to moisture and impurities in the air may complicate their widespread use. The work reported in this section describes the electrochemical behaviour of four simple gases (oxygen, ammonia, nitrogen dioxide and sulphur dioxide) in several different RTILs.…”

“…in acetonitrile, which in the presence of some RTILs, allows an extended anodic window compared to tetrabutylammonium perchlorate (TBAP). 8 Their low-volatility, high thermal stability and intrinsic conductivity make them potentially useful as electrolytes in gas sensors, 9 an application which will be discussed in more detail in section 5. RTILs are also used in a range of other electrochemical applications such as electrolytes in lithium batteries, 10 capacitors 11 and solar cells.…”

Electrochemical Behavior of Nanoelectrode Ensembles in the Ionic Liquid [BMIm][BF4]

“…ILs show interesting properties for electrochemical [9,10], electroanalytical [11 -14] and sensor [15] application. They are ionic aprotic solvents useful to dissolve water insoluble organics and metallorganics, to perform electrosynthesis and electroanalysis without the need of adding supporting electrolyte and avoiding parasitic reactions such as hydrogen evolution reaction which typically occurs in water solution at negative potential values.…”

Gold electrodeposition in organic media

“…This is related to the high viscosity of the medium. 37,38 A detailed analysis of P 1 will allow us to evaluate and quantify the interaction plotted against the square root of the scan rate, v, and log v, respectively. In Fig.…”