The effect of various diffusion barriers on the mass transport controlled current for an amperometric gas sensor with a porous membrane is considered. A general equation is derived which relates the total current to the diffusion parameters for each barrier. By varying the thickness of one barrier at a time, keeping all the other parameters constant, the relative roles of each of the barriers can be determined. This is done for CO and H 2 S sensors and in both bases it is shown that more than 70% of the transport control is provided by the electrolyte film in the porous electrode/membrane. This conclusion is supported by observations of the temperature dependence of the sensor currents. It is concluded that, in order to obtain more consistent and reproducible results from porous membrane covered amperometric gas sensors, a more controllable method of electrode manufacture and assembly would be desirable.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.