Influence of the catalytic introduction procedure on the nano-SnO2 gas sensor performances

Metal Oxide Nanoparticles

“…A wide range of different metal oxides [223,[228][229][230][231][232][233] and mixed oxides [38,228,229,232,234,235] have been investigated; however, tin oxide is probably the most common system due to the numerous gases it shows a response to. For example, tin oxide has been shown to respond to a wide range of flammable gases, including carbon monoxide, [236][237][238] hydrocarbons, [238][239][240] hydrogen [241,242] and other pollutant gases such as hydrogen sulfide [239,243] and nitrous oxides. [237,244] The use of metal oxide semiconductors as sensor materials is based on the change in resistance that is observed when they are exposed to oxidising or reducing gases.…”

“…As a result a range of techniques, such as doping or the addition of catalysts have been investigated to improve both sensitivity and selectively. In the case of tin oxide based materials, the most widely used catalysts are the noble metals Pd, [238,[248][249][250] Pt, [238,250,251] Au, [238] Rh [252] and Ru. [251,252] The use of catalysts may not generally improve the selectivity of a sensor material since they will oxidise most gases and vapour.…”

Ion‐Conducting Nanocrystals: Theory, Methods, and Applications

“…Consequently, a range of techniques, such as doping or the addition of catalysts, have been investigated to improve both sensitivity and selectively. The most widely used catalysts in tin oxide-based materials are the noble metals Pd [39,[62][63][64], Pt [39,64,65], Au [39,66], Rh [67], and Ru [65,67]. The use of a catalyst results in an increase in the sensitivity and speed of the response to flammable gases at low temperatures, while the hightemperature response is diminished [68].…”

“…While several methods have been investigated to overcome this limitation when using nanocrystalline tin oxide, two main approaches have been taken. The first method is to reduce the operating temperature of the sensor material by introducing secondary metal oxides or metal particles as surface catalysts [66,78]. The second method is to physically inhibit the grain growth by introducing a second metal oxide such as SiO 2 [83,84], Bi 2 O 3 [85], or In 2 O 3 [86] in the case of tin oxide.…”

Room temperature operation of ITO nano‐crystal gas sensor

“…However, nevertheless the various merits, the high resistivity of printed metal oxide layer constrains further improvement. Hence, various ways such as doping into the nano-crystals [6], adding the conductive additives [7], and high temperature annealing [8] have been investigated. Especially, pressurized high temperature annealing was found to be helpful for increasing the annealing temperature, which is crucial for the application of materials such as ITO, because the resistivity of it greatly depends on the annealing conditions [9].…”