Simple Route to Obtain Nanostructured CeO2 Microspheres and CO Gas Sensing Performance

Abstract

In this work, nanostructured CeO2 microspheres with high surface area and mesoporosity were prepared by the coprecipitation method, in absence of a template. The reaction between cerium nitrate and concentrated formic acid produced cerium formate, at room temperature. Further, calcination at 300 °C yielded single-phase CeO2 microspheres, with a diameter in the range 0.5–2.6 μm, the surface of these microspheres is completely nanostructured (diameter about 30–90 nm). CeO2 microspheres were used to fabricate a sensor device, and it was tested for intermediate CO gas concentrations (200–800 ppm). The detection of 200 ppm carbon monoxide was observed at 275 °C, with a response time of 9 s, using an applied frequency of 100 kHz. The detection of changes on the CO gas concentration was studied at different temperatures and applied frequencies. The results revealed a reproducible and stable gas sensing response.

Novel Approaches of Nanoceria with Magnetic, Photoluminescent, and Gas-Sensing Properties

“…After determining the working temperature, the resistance versus time (Figure ) behavior was studied at 400 °C, changing the atmosphere from vacuum to synthetic air (∼20% oxygen) and 50 mmHg of CO (99.99%). Particularly, a relatively fast response time of 5.5 s can be observed after CO exposure, slightly higher than the 2 s obtained with a sintered CeO 2 film at 950 °C but better than the 9 s reported by López-Mena et al with 300 °C-calcined films. The observed resistance decrease indicates an n-type semiconductor behavior of the doped material.…”

A Highly Sensitive and Room Temperature CNTs/SnO2/CuO Sensor for H2S Gas Sensing Applications

“…With the development of industrialization, emission pollution is becoming increasingly serious, so different types of gas sensors have been widely studied [1][2][3][4][5][6][7]. SnO 2 as a n-type and environment-friendly semiconductor has been studied by many different researchers [8][9][10][11].…”

Effect Synthesis Time of CeO2 Nanoparticles by Microwave-Assisted Hydrothermal as a Sensing Device on CO Gas Sensitivity

“…Cerium oxide (CeO 2 ) also called ceria is a promising compound for several technological applications mainly because its physical and chemical properties are easily modified through a control over the composition, type of structure, morphology, and size of the particles during its synthesis and process 1,2 . Some of the essential properties of this material are oxygen storage capacity, redox potential, thermal stability, chemical stability, low toxicity, electronic conductivity, and high oxygen mobility [3][4][5] .…”

“…These researchers concluded that vacuum promotes oxygen desorption on the CeO 2 nanoparticles surface, and that the electrons loss in the 4f state of cerium causes a reduction in electrical resistance. López-Mena et al 3 synthesized nanostructured CeO 2 microspheres by co-precipitation, testing their application in carbon monoxide detection. They obtained a response time of 9 s at 275 °C, for the 200 ppm CO detection at a 100 kHz frequency.…”