Designing oxide chemiresistors for detecting volatile aromatic compounds: recent progresses and future perspectives

Abstract

Rational strategies to design high-performance gas sensors for detecting aromatic compounds using oxide chemiresistors are reviewed, proposed, and discussed. The sensors suggested in this study will open up a new avenue for on-demand applications.

Exclusive detection of volatile aromatic hydrocarbons using bilayer oxide chemiresistors with catalytic overlayers

“…Under actual gas-sensing conditions, volatile aromatic compounds (BTEXS) coexist with different concentrations of airborne chemicals, which often hinders quantifying gas concentrations 1 , 2 , 12 , 64 . To determine the reliable sensing under interferant, the sensor responses to 5 ppm of pure B, T, E, X, or S and the same in mixed gases were measured at 300 °C by varying the interfering-gas type and concentration i.e., 0.1–5 ppm of ethanol, HCHO, or acetone (Fig.…”

“…The sensor temperature required to achieve the maximum gas response ( T M ) also supports the proposed mechanism. Oxide chemiresistor response curves plotted as functions of sensing temperature are usually bell-shaped 12 , 69 , 70 . For instance, in the low-sensing-temperature region, the gas response gradually increased through the thermal promotion of the sensing reaction between the analyte gas and ionized surface O atoms.…”

“…6 ). The VAH catalytic conversions were gradually promoted by increasing the temperature because stable aromatic compounds catalytically oxidize more predominantly at high temperatures 12 , 63 , 64 , 71 , 72 . Interestingly, in the range 250–350 °C, the VAHs with high molecular stability were not fully oxidized by the CeO 2 catalyst (Fig.…”

Exclusive detection of ethylene using metal oxide chemiresistors with a Pd–V2O5–TiO2 yolk–shell catalytic overlayer via heterogeneous Wacker oxidation

“…Among these, since the operating temperature of metal oxide chemiresistors is relatively high (200–400 °C), they have distinct advantages in promoting the sensing of less reactive ethylene by thermal activation. 28 However, owing to the high chemical stability and simple structure of ethylene, it is highly difficult to achieve sensitive gas detection. Another major challenge is that a simple sensing mechanism based on the charge transfer between the analyte gas and metal oxide surface prevents selective gas sensing.…”

Acetone and Toluene Gas Sensing by WO3: Focusing on the Selectivity from First Principle Calculations

“…The growing concerns in reliable detection of gaseous species have led to the development of newly emerged gas sensors for a wide variety of applications, such as environment pollution monitoring, air quality investigating, medical diagnostics, food technology, etc. [ 1 ]. Particularly, chemoresistive sensors [ 2 ] have attracted the scientific community due to their good response (down to ppb), ease in synthesis, and cost effectiveness.…”