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A QM/MM study of NO oxidation on the nanocrystalline surface of tungsten oxide

Posted on 5. March, 2015.

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Nitrogen oxides play a major role in air pollution, particularly in the creation of acid rain and photochemical smog. Among the methods that can be used to capture or eliminate these pollutants are adsorption on the surfaces of metal oxide semiconductors (MOSs) and followed by conversion into other materials.

Many MOSs have been widely investigated as gas-sensing materials, such as tungsten oxide (WO3), that have suitable properties. Semiconductor metal oxide sensors possess merits such as easy implementation, low cost, good reliability and enabling real-time measurements. Tungsten (VI) oxide (WO3) is a semiconducting metal oxide with a wide band gap. It shows various chemical and physical properties that find applications in electrochromic display (field emission devices), photocatalysis and gas sensors. Gas sensors based WO3 can detect small quantities of NOx, NH3, O3, H2 and so on. These devices work by measuring the resistivity changes of the sensitive layer under different atmospheres.Chemical sensors based on tungsten oxides have received increasing attention as they can monitor low concentrations of various kinds of gases. They are reported to be favourable choices for detecting NO2, H2S, O3, NH3, and liquefied petroleum gas when operated at elevated temperatures.

Read the full article in Progress in Reaction Kinetics and Mechanism, Volume 40, Number 1, 2015, pp. 69-76

Authors: Mohammad Izadyar* and Rahim Balgerdi
Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, Iran

Keywords: surface adsorption, Fermi-level, sensor, density functional theory, band gap, tungsten oxide


Image: Optimised structure of cubic WO3