Gas Sensing Characteristics of ZnO-doped SnO₂ Sensors for Simulants of the Chemical Agents

Abstract

After the 9∙11 terrorism and America-Iraq war, apprehension of mass destruction weapons such as bio-chemical agents calls for much more sensitive sensors which can detect toxic gases. In this study, semiconductor gas sensors based on tin oxide were examined to detect chemical agent simulants: dimethyl-methyl-phosponate (DMMP), di(propylene glycol) methyl ether (DPGME), acetonitrile, and dichloromethane. DMMP((CH3O)3), DPGME(C7H16O3), acetonitrile(CH3CN), and dichloromethane(CH2Cl2) gases are the simulants of nerve agent-sarin, vesicant agent-HN(N(CH2CH2Cl)3), blood agent-AC(HCN), and choking agent-CG(COCl2) gases, repectively. The SnO2 powder was prepared by a coprecipitation method from the mixture of tin chloride and zinc acetate dihydrate. Zinc oxide was doped into SnO2 from 1 wt% to 4 wt% to improve its reliability and sensitivity. To fabricate a thick film, powders were made into paste with organic binder of ethyl cellulose and screen-printed on the alumina substrate. The phase development and morphology of ZnO-doped SnO2 film were investigated by XRD (X-ray diffraction analysis), BET (surface and pore size analyzer), and SEM (scanning electron microscope). The gas sensing characteristics for target gases were examined with a flow-type measurement system. The concentrations of simulants were controlled from 500 ppb to 1500 ppb, and working temperatures were regulated from 250 to 400 .

Study of a QCM Dimethyl Methylphosphonate Sensor Based on a ZnO-Modified Nanowire-Structured Manganese Dioxide Film

“…These details indicate the nanostructured metal oxides like TiO 2 , ZnO and MnO 2 may show sensitive and dissociative adsorbent of gas-phase DMMP at ambient temperature, promising sensing behavior for the mass detection of gas-phase organophosphorus compounds. However, only a few experimental studies have been reported on the adsorption of toxic chemicals or chemical warfare agent simulants on nano-structured MnO 2 at ambient temperature [ 40 ].…”

“…In addition, it is interesting that the behavior of alumina-supported iron oxide may be significantly different from that of pure alumina [ 32 , 33 ]. Furthermore, zinc oxide doped in SnO 2 may improve the reliability and sensitivity of the SnO 2 sensors for simulants of the CWAs at 250 to 400 °C [ 40 ]. It is suggested that the absorption capability of DMMP on MnO 2 surface is possibly improved by ZnO modification.…”

Metal Oxide Nanosystems As Chemoresistive Gas Sensors for Chemical Warfare Agents: A Focused Review

“…Over the past decades, tin dioxide (SnO 2 ), an n-type semiconductor, has been the most investigated material for gas detection owing to its high sensitivity, rapid response time, low cost, and high chemical stability. [52,76,78,79,94,[113][114][115] As regards tin dioxide use for CWA simulant sensing, efforts have been initially devoted to thick films [5,27,47,52,64,76,78,79,83] and, subsequently, to 1D SnO 2 nanostructures, such as nanobelts, nanowires, and nanorods, [28][29][30]56,90,116] promising building blocks to develop a new generation of metal oxide gas sensors. As concerns the former, various literature works have reported on SnO 2 -based thick film, eventually mixed with Al 2 O 3 , In 2 O 3 , ZnO, ZrO 2 , Nb 2 O 5 , Pd, Pt, [27,47,78,117,118] Co 3 O 4 , Nb 2 O 5 , MoO 3 , NiO, Sb 2 O 3 , [52] or MoO 3 , Sb 2 O 3 , and NiO.…”

“…[52,76,78,79,94,[113][114][115] As regards tin dioxide use for CWA simulant sensing, efforts have been initially devoted to thick films [5,27,47,52,64,76,78,79,83] and, subsequently, to 1D SnO 2 nanostructures, such as nanobelts, nanowires, and nanorods, [28][29][30]56,90,116] promising building blocks to develop a new generation of metal oxide gas sensors. As concerns the former, various literature works have reported on SnO 2 -based thick film, eventually mixed with Al 2 O 3 , In 2 O 3 , ZnO, ZrO 2 , Nb 2 O 5 , Pd, Pt, [27,47,78,117,118] Co 3 O 4 , Nb 2 O 5 , MoO 3 , NiO, Sb 2 O 3 , [52] or MoO 3 , Sb 2 O 3 , and NiO. [79] In these cases, sensing devices were manufactured via screen-printing, and their properties were tested toward the detection of DMMP, di(propylene glycol) monomethyl ether (DPGME), acetonitrile (ACN), and DCM.…”

“…the hands of terrorists, and their recurring use makes them a contemporary and persistent hazard. [8,13,[23][24][25][26][27] Examples in this regard include nerve agents release in Japan (Matsumoto, 1994 andTokyo, 1995), [2][3][4][36][37][38][39][40] Al Qaeda threats, [41] the assassination of Kim Jong-Nam, the half-brother of North Korean leader Kim Jong-un, at Kuala Lumpur Airport (Malaysia) in 2017, [42,43] and the poisoning of the Russian spy Sergei Skripal and his daughter in Salisbury (UK) in 2018. [44] Highly lethal CWAs, that can be classified into four main categories (see Table 1; nerve, blood, vesicant, and choking agents [2,4,5,10,17,28,[45][46][47][48] ) can burn and blister skin/eyes, enter into the body in blood and attack the nervous system.…”