Study of the surface-ruthenated SnO2/MWCNTs nanocomposite thick-film gas sensors

Nanocomposite sensors of propylene glycol, dimethylformamide and formaldehyde vapors

“…Furthermore, the crystalline structure of the inorganic layer was also studied by an X-ray diffraction method using the Rigaku Miniflex II diffractometer (angle range: 2θ = 10-80 • , utilizing characteristic X-ray (CuKα) radiation). Results of these investigations were presented in detail in the Aroutiounian's articles (Aroutiounian et al, 2013(Aroutiounian et al, , 2014. Here, we are only noting that the average crystalline size of SnO 2 nanoparticles, estimated from SEM images and XRD patterns, is less than 12 nm, but the average diameter of non-covered SnO 2 nanoparticles CNTs was about 40 nm.…”

“…At the end of this procedure, all obtained nanocomposite powders were filtered and dried at 90 • C for 5 h. The final mass ratio of the nanocomposite MWCNTs/SnO 2 obtained with the hydrothermal method in this study was 1 : 200. The hydrothermal synthesis process is presented in detail again in articles mentioned above (Aroutiounian et al, 2013(Aroutiounian et al, , 2014Nemeth et al, 2014a).…”

“…Then, the annealing treatment was carried out again by the same method noticed above. The choice of the ruthenium as a catalyst was determined by the advantages outlined in Aroutiounian et al (2013Aroutiounian et al ( , 2014 and Adamyan et al (2016). At the final stage, ruthenated MWCNT/SnO 2 chips were arranged in TO-5 packages, and the gas sensors would be ready for measurements after the bonding of leads.…”

“…Our recent works related to the study of gas sensors based on multiwall carbon nanotubes/tin oxide (MWCNTs/SnO 2 ) nanostructures are also supported by Aroutiounian et al (2013Aroutiounian et al ( , 2015 and Adamyan et al (2016). The choice of tin-oxide as a component of SnO 2 /MWCNT nanocomposite structure is conditioned by the fact that SnO 2 is a well-known basic material for metal-oxide gas sensors (Korotcenkov et al, 2009;Aroutiounian, 2007;Shankar et al, 2015).…”

“…Meanwhile, pure metal oxide structures react on FA at higher operating temperatures (300-400 • C) (Xu et al, 2014;Park et al, 2014) or room temperature with the assistance of UV LEDs (Chung et al, 2014;Li et al, 2015). Nanomaterials, such as carbon nanotubes (CNTs), metaloxide nanoparticles, nanotubes, nanowires and other various nanopattern formations are widely used in gas sensing structures due to their excellent responsive characteristics, mature preparation technology and low cost of mass production (Aroutiounian, 2015;Arafat et al, 2012;Korotcenkov et al, 2009;Aroutiounian et al, 2013;Feyzabad et al, 2012;Hieu et al, 2008). When CNTs' walls are covered with metal-oxide nanoparticles, the specific surface area of sensitive gas material enlarges.…”