Use of air/platinum as the reference electrode in solid oxide electrolyte e.m.f. measurements

The electrode, air (Po(2)approximate to 21.222 kPa)/Pt is often used as a r eference electrode in numerous applications in oxygen gauges and coulometri c devices which make use of zirconia based solid electrolytes. In recent ye ars, a large number of thermodynamic measurements have been reported using the zirconia electrolyte based e.m.f. technique with this reference electro de. This review summarizes the merits, limitations, mechanistic aspects, pr ecautions to be taken and the sources of error in the use of air/Pt electro de for thermodynamic measurements. In addition, a brief survey of recent ap plications of air/Pt electrode is presented, together with recommendations for the proper use of the omnipresent air as an oxygen fugacity standard. ( C) 2000 Elsevier Science Ltd. All rights reserved.