The development of new microelectrode gas sensors: an odyssey. Part 1. O2 and CO2 reduction at unshielded gold microdisc electrodes

Abstract

In this paper we describe the reduction of O2 and CO2, when both molecules are always present and the balance gas is N2, at unshielded gold microdisc electrodes in dimethyl sulphoxide (DMSO) in a standard reaction cell. We show that both gases can be reduced in the presence of each other, in the range 3–15 vol.% CO2 and 10–30 vol.% O2, with minimal cross-interference from “feedforward” and “feedback” reaction products from the individual O2 and CO2 reduction processes. Well-separated O2 and CO2 reduction processes were obtained with gold microdisc electrodes when the polarizing voltage was swept typically at 0.1–0.5 V s−1, and steady state limiting currents were measured which were proportional to the O2 and CO2 concentrations.