Abstract
Gas sensing properties of metal oxide nanopowders (ZnO, TiO2, WO3, SnO2) with average diameters of 40–60 nm were analyzed by room-temperature photoluminescence spectroscopy. The influence of gas environment (O2, N2, H2, CO, CO2) on the emission intensity was investigated for metal oxide nanopowders with surface doped by impurities (Pt, Ag, Au, Sn, Ni or Cu). Established physicochemical regularities of modification of surface electronic states of initial and doped nanopowders during gas adsorption. The nature of metal oxide nanopowder gas-sensing properties (adsorption capacity, sensitivity, selectivity) has been established and the design and optimal materials for the construction of the multi-component sensing matrix have been selected.
Highlights
Sensors for active, in particular, toxic and explosive gases play an important role in the monitoring and control of the environment, especially in highly industrialized regions
The metal oxide nanopowder samples were obtained by means of pulse laser-reactive technology [17, 19]
The character of visible photoluminescence determined by the intrinsic defect structure of the material and depends on the technological parameters obtaining of nanopowders [26]
Summary
Sensors for active, in particular, toxic and explosive gases play an important role in the monitoring and control of the environment, especially in highly industrialized regions. Gas sensors based on nanostructured metal oxides have shown great potential for the detection of different gases, in particular, toxic, hazardous, or inflammable gases such as H2, CO, NO2 or NH3 [1,2,3]. Such sensors can be applied in medicine, for diagnosis of cancer [4]. Metal oxide nanopowders are of interest as nontoxic, easy-to-handle, and highly sensitive materials that can be grown with excellent crystal quality using different physical and chemical fabrication techniques [8,9,10,11,12]. The use of different cover metal layers (Pt, Ag, Au, Sn, Ni or Cu) as catalysts for gas chemisorption or physisorption can achieve an increase in the detection limit for specific gases and could be in the range of parts per billion (ppb) [13,14,15]
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