Amperometric oxygen sensors: problems with cathodes and anodes of metals other than silver

Abstract

The ideal diffusion geometry of the metallised membrane electrode is used to show that silver is the ideal material for oxygen measurement with an amperometric sensor. Gold by itself has no particular advantages over silver, while the commonly used platinum suffers both from a low overvoltage for hydrogen evolution and usually from low catalytic activity for oxygen reduction to hydroxide ion. Problems arising from the use of a two-electrode “galvanic” system are discussed.