A comparative study on the electrical and gas sensing properties of thick films prepared with synthesized nano-sized and commercial micro-sized Fe2O3 powders

Abstract

In this work, Fe2O3 nanoparticles (NPs) were successfully synthesized by Pechini sol-gel method. Scanning electron microscopy, transmission electron microscopy and X-ray diffraction characterizations were used to study the morphology and crystal structure of the synthesized products. The electrical and gas sensing behaviour of the synthesized and commercial Fe2O3 samples, prepared in the form of thick films, were studied. Though the commercial Fe2O3 powders had lower resistance but it was found that the synthesized Fe2O3 NPs had better gas sensing properties. The underlying mechanisms are discussed in details. The present findings show advantages of Fe2O3 NPs over micro-size particles for gas sensing applications.

Effect of Carrier Gas on the Gas Sensing Performance of Co1−2xNixMnxFe2−yCeyO4 Double-Substitution Spinel in Flammable Gases and Volatile Organic Compounds

“…When the target gas (LPG, which is a reducing gas) was introduced into the chamber, it reacted with the chemisorbed oxygen on the sensor surface to produce water and carbon dioxide (Figure 7b). The surface reduction in the sensor's sensing layer led to the release of the captured electrons, causing the thinning of the depletion layer and resulting in increased conductivity of the sensor [39][40][41]. When helium was used as the carrier gas (Figure 7c), the sensor resistance (27.95 kΩ) was observed to be far lower than that observed when air was used (see Table 3).…”

“…At an operating temperature of 225 • C, atmospheric oxygen is chemisorbed on the surface of the sensor as Ooxygen species (Figure 7a), as illustrated in Equations ( 2)-( 5). These oxygen species capture the free electrons at the conduction band, creating a depletion layer on the sensor [39,40], and thus increase the resistivity of the n-type sensor. When the target gas (LPG, which is a reducing gas) was introduced into the chamber, it reacted with the chemisorbed oxygen on the sensor surface to produce water and carbon dioxide (Figure 7b).…”

Development of an Integrated In-Vehicle Driver Breath Ethanol System Based on α-Fe2O3 Sensing Material

“…Many examples of ethanol sensors have been developed and show a remarkable sensing capacity [6][7][8]. In particular, we have shown that α-Fe 2 O 3 is an ideal candidate as a sensing material to be used in breath ethanol conductometric sensors [9,10].…”