Investigation of electronic and chemical sensitization effects promoted by Pt and Pd nanoparticles on single-crystalline SnO nanobelt-based gas sensors

Electrospun Metal Oxide Nanofibers and Their Conductometric Gas Sensor Application. Part 2: Gas Sensors and Their Advantages and Limitations

“…An explanation of the observed behavior of sensors after decorating the surface with noble metals can be found in [35,186,188,[199][200][201][202][203][204][205][206][207][208]. Typically, these explanations suggest the presence of two sensitization mechanisms proposed by Morrison [34] and Yamazoe [29].…”

“…However, the roles of sensitizers and sensitization mechanisms are not always clear. For example, Barbosa et al [208] found that both electronic and chemical sensitization effects are relevant in Pt-decorated SnO 2 devices. Degler et al [207] also believe that the separation of electronic and chemical sensitization is useful for the first assessment of the role of additives, but for a complete understanding of reality, it is necessary to take into account the mutual influence of chemical and electronic properties and processes.…”

“…It is important to keep in mind that the activity of noble metals depends on many factors. These include parameters such as the coating thickness, cluster size, concentration of oxygen vacancies in the metal oxide support, interaction with the support, the method used to decorate the surface of metal oxides, the temperature of post-treatment and even the surface morphology and concentration of structural defects in the metal oxide itself [202][203][204][205][206][207][208]. For example, Katoch et al [189] believe that the high sensitivity and selectivity of the response to CO of sensors based on electrospun SnO 2 nanofibers decorated with Au were achieved due to the extremely small size of both the SnO 2 crystallites and gold clusters, and the high density of Au nanoparticles on the surface of the SnO 2 nanofibers (see Figure 13).…”

Effect of Ag Addition on the Gas-Sensing Properties of Nanostructured Resistive-Based Gas Sensors: An Overview

“…Typically, the electronic sensitization effect depends on the presence of a junction potential barrier between the semiconductor and the noble metal. Differences between the Fermi levels of the SMO and the catalyst cause the depletion or accumulation of charge carriers at the semiconductor, adjacent to the particles, because of the pinning effect [ 41 , 42 , 43 ]. When the oxidation state of a noble metal, including Ag, changes with respect to the surrounding atmosphere, the electronic state of the semiconductor accordingly varies because Ag can form Ag 2 O or AgO in air, whereas Ag 2 O or AgO is simply reduced to metallic Ag when exposed to a reducing gas.…”

Comparative Study on the Effect of Protonation Control for Resistive Gas Sensor Based on Close-Packed Polypyrrole Nanoparticles

“…In the past few decades, chemical gas sensors have been widely used in several applications, including the detection of combustible, flammable, and toxic gases [1][2][3][4][5]. Various semiconductive materials are used as transducers for chemical sensors, and extensive investigations have been conducted to improve their performance [6][7][8][9]. The critical indicators for sensor performance include high sensitivity to the target analyte, short response and recovery times, and cycle stability [10,11].…”