Mechanism of Fast NO Response in a WO3-Nanorod-Based Gas Sensor

Abstract

The development of fast and reliable gas sensors is a pressing and growing problem for environmental monitoring due to the presence of pollutants in the atmosphere. Among all gases, particular attention is devoted to NO, which can cause serious health problems. WO3 nanorods represent promising candidates for this purpose due to their high electrical stability and low cost of production. Here, the hydrothermal synthesis of WO3 nanorods is reported, in addition to the realization of a chemo-resistive NO sensor. NO-sensing tests were performed at different temperatures (250–400 °C) and under different gas concentrations (250–2500 ppm), and NO response and recovery curves were also modeled by using the Langmuir adsorption theory by highlighting the NO-sensing mechanism of the WO3 nanorods. An interaction occurred at the surface between NO and the adsorbed oxygen ions, thus clarifying the NO-reducing behavior. The fast response and recovery times open the route for the development of fast NO sensors based on WO3.

Structural Design of Dual-Type Thin-Film Thermopiles and Their Heat Flow Sensitivity Performance

“…Wherein, the response time is the time from the exposure of the thermofluid meter to a heat flow of a given power to the output stabilizing the output voltage under test conditions; typically, the time to reach 90% of the maximum value is read as the response time. Whereas, the recovery time is the time from when the thermofluid meter is no longer in contact with the heat flow to when the output returns to a steady state under test conditions; typically, the time to recover to 10% of the maximum value is read as the recovery time [ 35 , 36 ]. In addition, the magnitude of the output voltage shows good agreement with the simulation calculations.…”

Advances in WO3-Based Supercapacitors: State-of-the-Art Research and Future Perspectives

“…This aspect is crucial within a life cycle assessment analysis, taking into consideration recycling and decreasing waste, or in cases in which noble metals or critical raw materials (CRMs) are used [26]. The use of nanostructures contributed to the brilliant recent scientific results on WO 3 for energy storage, electrochromism, photocatalytic, and sensing applications [19,[27][28][29][30][31][32][33][34].…”