Control of Electrode Reactions in a Mixed-Potential-Type Gas Sensor Based on a BiCuVOx Solid Electrolyte

Abstract

Mixed-potential-type gas sensors are promising solid-state devices for the in-situ detection of ppm concentrations of air pollutants in the atmosphere. In this study, we designed electrode structures of mixed-potential-type sensors using a BiCuVOx (Bi 2 V 0.9 Cu 0.1 O 5.35 ) solid electrolyte to control the responses of electrodes to organic gases. Devices fitted with sensing and counter electrodes made of a composite of BiCuVOx and a perovskitetype oxide (La 0.6 Sr 0.4 Co 0.8 Fe 0.2 O 3 ) were fabricated and tested for their ethanol-sensing properties. Sensor devices with a three-electrode configuration, in which a reference electrode was exposed to a standard air mixture, were fabricated to separately measure the potentials of the sensing and counter electrodes relative to the reference electrode. When a thin (30 µm) sensing electrode and a thick (68 µm) counter electrode were attached to a planar device, the sensing electrode exhibited high responses to ethanol at 350 and 400 °C. However, the overall signal was still small because the counter electrode also responded to ethanol. In another planar device in which the counter electrode was coated with a Pt/Al 2 O 3 catalyst, the counter electrode exhibited almost no response to ethanol resulting in the generation of large sensor signals. This is because the catalyst layer efficiently decomposed ethanol and impeded its diffusion to the reaction interface between the counter electrode and the solid electrolyte. The device coated with the combustion catalyst also showed good response and recovery speeds and high stability under humid conditions indicating its feasibility as a practical, compact ethanol sensor.

Solid Electrolyte Gas Sensor Based on a Proton-Conducting Graphene Oxide Membrane

“…41 Control of the microstructure and thickness of the sensing electrode would lead to sensor responses to various gases, such as ethanol and toluene, as reported for high-temperature mixed-potential-type gas sensors. 42 The response to oxygen was also examined in the absence of hydrogen. The GO sensor responded to oxygen, as shown in Figure 5a.…”

“…In contrast, the diffusion rate of hydrogen is probably high even in such a thick film electrode . Control of the microstructure and thickness of the sensing electrode would lead to sensor responses to various gases, such as ethanol and toluene, as reported for high-temperature mixed-potential-type gas sensors . The response to oxygen was also examined in the absence of hydrogen.…”

Facile preparation of polyaniline nanofibers modified bentonite nanohybrid for gas sensor application

“…According to Kida et al the electrode material should be chosen carefully to enable gas sensing selectivity. 35 The change of resistance of the electrodes (alone) on exposure to the acetone using both Ru (Fig. S3c 3 ) and Ag (Fig.…”

Quasi-Equilibrium, Multifoil Platelets of Copper- and Titanium-Substituted Bismuth Vanadate, Bi2V0.9(Cu0.1−xTix)O5.5−δ, by Molten Salt Synthesis

“…It was later found that a partial substitution of an aliovalent metal cation for vanadium (first was copper at 10 mol %) resulted in the stabilization of the γ-phase at room temperature, and the term BIMEVOX was coined to refer to this and all subsequent formulations, where ME represents one of the many possible substitutive metal cations, typically a transition metal [2]. Having an oxide ion conductivity that is higher than any other ceramic (e.g., yttria-stabilized cubic zirconia (Zr 1−x Y x O 2−x/2 "YSZ") at moderate temperatures, BIMEVOX compounds have generated interest over the years for their potential applications as solid oxide fuel cells, as oxygen separation pumps, as gas sensors [5][6][7][8][9], and very recently, as catalyst supports [10].…”