A Theoretical Insight of Cr Dopant in Tungsten Oxide for Gas Sensor Application. (September 2021)

• Record Type: Journal Article
• Authors: Syaahiran, A.; Lim, Chee Ming; Kooh, Muhammad Raziq Rahimi; Mahadi, Abdul Hanif; Chou Chau, Yuan-Fong; Thotagamuge, Roshan
• Is Part Of: Materials today communications. Volume 28(2021)
• Publication Date: 2021-09
• Subjects: Density functional theory -- WO3 -- Cr dopant -- Carbon monoxide -- Selectivity -- Sensitivity; Materials science -- Periodicals; 620.11
• DOI: 10.1016/j.mtcomm.2021.102508
• Languages: English
• ISSNs: 2352-4928

Abstract

Graphical abstract: Highlights: Impact of Cr dopant in (WO3 ) n ( n = 2 – 4) for adsorption of CO, H2 S and H2 . CrW n -1 O n ( n = 2 – 4) are relatively having lower energy gaps and high reactivity. Highest sensitivity observes with CrWO6 cluster and more selective towards CO gas. CrWO6 cluster is a potential and novel material for an effective CO gas sensor. Abstract: This is a study on the impact of Cr dopant in (WO3 ) n ( n = 2 to 4) on the sensitivity and selectivity of gas sensing. The theory is based on density functional theory (DFT) at the B3LYP/LanL2DZ level. The results show the chromium doped tungsten oxide clusters, (CrW n -1 O3 n ) ( n = 2 to 4), to have lower energy gaps, high reactivity, reduced stability, and demonstrates a higher ability to accept electrons from CO, H2 S and H2 gases when compared to the undoped (WO3 ) n ( n = 2 to 4) cluster. The results showed that the highest sensitivities for the three gases; CO, H2 S and H2, are observed with the CrWO6 cluster and the sensitivities of CrWO6 to CO, H2 S and H2 are 6.20E + 13, 2.32E + 12, and 4.11E + 05, respectively. The study also shows a decrease in gas sensing ability when the cluster size and the dopant density are increased. In the case of CO sensing, the CrWO6 cluster is shown to have exhibits the highest sensitivity. This is attributed to a dramatic change in energy gaps between pre-adsorption and postadsorption.