The development of a membrane-covered microelectrode array gas sensor for oxygen and carbon dioxide measurement

The simultaneous electrochemical reduction of oxygen and carbon dioxide at −1.5 and −2.5 V vs. Ag, respectively, has been investigated on two different, gold microelectrode arrays, one with 37 electrodes of diameter 20 μm and the other with 256 electrodes of diameter 5 μm. The arrangement of a practical sensor design incorporating a porous polytetrafluoroethylene (PTFE) membrane-covered gold microelectrode array is described for the simultaneous measurement of O2 and CO2. Linear sweep voltammetry and chonoamperometry techniques were applied in these studies, using propylene carbonate (PC) as the electrolyte. It was demonstrated that short voltage pulses (50 ms) and gold microelectrode arrays can be successfully used, in a practical sensor design, to interrogate the electrochemical reduction of both oxygen and carbon dioxide individually, and measure their concentrations in tertiary gas mixtures.