Cobalt nanograins effect on the ozone detection by WO3 sensors

Temperature and acidity effects on WO3 nanostructures and gas-sensing properties of WO3 nanoplates

“…However, so far, no reference has been found concerning the effects of both hydrothermal temperature and the amount of acid on crystal phases and morphologies of WO 3 nanostructures. WO 3 nanostructures could be extensively applied in electrochromic and photochromic devices [6,[17][18][19][20], lithium ion batteries [21][22], photoelectrodes [23], photocatalysts [24][25][26], solar energy devices [27][28], field electron emission [29][30] and gas sensors [1,10,13,14,16,[31][32][33][34][35][36][37][38][39][40][41][42] etc. Being one of the important gas-sensor materials, more and more WO 3 nanomaterials with new structures or morphologies have been synthesized because the gas-sensing properties could be tuned by the structures and morphologies of the materials.…”

“…For instance, WO 3 nanowires [10], nanofibers [13], hollow microspheres [31], nanocrystals [32,33], thin films [34] and WO 3 nanorods/graphene nanocomposites [35] have been used as the sensing materials for detection of nitrogen oxides, NH 3 and ethylene. More gaseous species, such as H 2 [14,34,36], ethanol [1,14,37,38], CO [14,37], H 2 S [39], and ozone [37,40] could also be detected by WO 3 -based nanocrystals and films. However, so far there are few reports on acetone [14,41] and formaldehyde [14] sensing properties of WO 3 nanoplates although acetone and formaldehyde are harmful to health, as common reagents widely used in industries and labs.…”

Facile Solvothermal Synthesis and Gas Sensitivity of Graphene/WO3 Nanocomposites

“…However, the range of application of WO 3 gas sensors is limited by poor selectivity, long response time, low sensitivity and high resistivity. Although methods, such as reduction of grain size, use of novel synthesis morphology, addition of dopants, and use of mixed sensing materials, have been adopted to enhance the sensing properties of WO 3 , fewer contributions have been made to reducing the high resistivity of WO 3 -based sensors [21,22]. …”

Attachment of Metal Nanoparticles to SnO<SUB>2</SUB> Nanowires for Enhancement of Gas Sensing Properties

“…19 In the electronic sensitization mechanism, on the other hand, the Co nanoparticles will directly enhance the electron transfer between the adsorbed gas species and underlying SnO 2 surface, by means of the change of the oxidation state. 27 Similarly, the Co-indueced enhancement in the ozone detection of WO 3 sensors is attributed to the change of the oxidation of states of Co. 18 Jing et al suggested that the enhancement of gas sensing properties (for CH 4 , H 2 , and CO) of Co-doped Fe 2 O 3 is associated with the change of the oxidation state of CO (i.e., electronic sensitization), in addition to the increase of the Debye length by repacing a part of Fe 3+ by Co 2+ ions. 14 When the NO 2 gas is introduced, the depletion layer in SnO 2 will be enlarged by means of two mechanisms.…”