Promoted Carbon Monoxide Sensing Performance of a Bi₂Mn₄O₁₀-Based Mixed-Potential Sensor by Regulating Oxygen Vacancies

Abstract

The YSZ-based mixed-potential sensor has exhibited promising application prospects for in situ carbon monoxide (CO) monitoring owing to its excellent thermal stability. However, the way to further enhance the sensitivity and selectivity of the sensor remains challenging due to the limitation of the sensing material. In the present work, we proposed a strategy of introducing moderate oxygen vacancies in the transition metal oxide sensing material to enhance CO sensing performance. More importantly, the oxygen vacancies of the sensing electrode were regulated by adjusting the volatilization of the Bi element at different sintering temperatures. Meanwhile, the stable mullite structure and variable valency of Mn were also exploited to maintain the phase structure stability and charge balance brought by the loss of Bi. The relationship between CO sensing properties and the proportion of both Mn3+/Mn4+ and oxygen vacancies was elucidated from XPS and EIS measurements. By contrast, the 800 °C-sintered Bi2Mn4O10 possesses the highest oxygen vacancy content and thus exhibits preferable sensing performance including a lower detecting limit (10 ppm), swifter response/recovery processes, and enhanced CO sensitivity (−70.47 mV/decade operated at 450 °C) with satisfactory selectivity and stability, indicating a promising prospect for CO monitoring under exhaust environments.

Defective WO3 Nanosheets with (002)-Exposed Facet for Highly Sensitive Acetone Detection

“…Another effective strategy to realizing high-performance WO 3 sensors is to control oxygen vacancies. According to previous studies, oxygen vacancies seem to act as active sites for adsorbing molecular species. , To further investigate the influence of crystal facet and oxygen vacancies on the gas sensing properties simultaneously, theoretical calculations were adopted. It should be noted that the (002) is the highest energy facet in monoclinic WO 3 and rich in unsaturated coordination W atoms, which can provide more active sites .…”

The Future of Engineered Living Sensors ─ I Hope It Is Not the Thing with Feathers

“…The last individuals in this class of living sensors were retired in 1986 in favor of less romantic but substantially more humane electronic devices . Improvements to the nonliving sensors for carbon monoxide continue to this day, such that their capabilities now far exceed the humble canary in terms of sensitivity and reliability. While gas phase carbon monoxide may not be the most ideal target analyte for a living sensor, there are other analytes and sensing scenarios where engineered living sensors play a critical, enabling role that cannot be duplicated with a “dead” systemdrug toxicity screening is an application with perhaps the most prominent examples .…”