Abstract
In recent years, exhaust sensors have become increasingly attractive for use in energy and environmental technologies. Important issues regarding practical applications of these sensors, especially for soot measurements, include the further development of ion-conductive electrolytes and active electrode catalysts for meeting performance and durability requirements. Herein, we design a proton conductor with a high breakdown voltage and a sensing electrode with high sensitivity to electrochemical carbon oxidation, enabling continuous soot monitoring with self-regeneration of the sensor. A Si0.97Al0.03HxP2O7-δ layer with an excellent balance between proton conductivity and voltage endurance was grown on the surface of a Si0.97Al0.03O2-δ substrate by reacting it with liquid H3PO4 at 600 °C. Specific reactivity of the electrochemically formed active oxygen toward soot was accomplished by adding a Pt-impregnated Sn0.9In0.1HxP2O7-δ catalyst into a Pt sensing electrode. To make the best use of these optimized materials, a unipolar electrochemical device was fabricated by configuring the sensing and counter electrodes on the same surface of the electrolyte layer. The resulting amperometric mode sensor successfully produced a current signal that corresponded to the quantity of soot.
Highlights
In recent years, exhaust sensors have become increasingly attractive for use in energy and environmental technologies
The crystal structure of Al-doped SiO2 synthesized at 1400 °C was determined by X-ray diffraction (XRD) to be primarily cristobalite (Figure S1)
We conclude that the maximum solid solubility of Al for this system is 3 mol%
Summary
Exhaust sensors have become increasingly attractive for use in energy and environmental technologies. Several simpler potentiometric and amperometric soot sensors that employ solid electrolytes (yttria-stabilized zirconia[8,9] and SnP2O710–13), an electrical insulator (alumina)[14,15,16], or a semiconductor (GaN)[17] have been proposed One such sensor, which consists of proton-conducting Sn0.9In0.1HxP2O7-δ or SnP2O7-SnO2 solid electrolyte, produces active oxygen at a Pt sensing electrode via the anodic water vapor oxidation reaction. This oxygen species shows catalytic activity for carbon oxidation at temperatures of 50 °C or higher:. The weak soot sensing properties of currently used electrodes are primarily due to the poor kinetics of the platinum black catalyst used in Reaction (1), which in turn results from the limited number of reaction sites available for soot oxidation on the catalyst surface
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
