Au, Ag and Cu doped BNNT for ethylene oxide gas detection: A density functional theory study

Ethylene oxide (abbreviated as EO and Eto, with the formula C2H4O) is a colorless, flammable, water-soluble poisonous gas discovered in 1859 and with an ether-like sweet odor. Especially in living creatures exposed to ethylene oxide vapor, it irritates the skin, eyes and respiratory system for a short time, can cause allergic reactions, can cause burns, causes nausea and vomiting, and acts on the central nervous system. It is very important to detect it in the environment for reasons such as damaging the DNA and causing permanent diseases in humans. Boron-nitride nanotubes (BNNTs) are obtained by reacting with ammonia and nitrogen to form boron nitride (BNNT) at high temperatures. In addition to its structural features, its mechanical properties are also highly developed. BNNTs are semiconductors, have high oxidation resistance, are small in size, require very little power to operate, have high detection capacities, and are used as gas sensors for many reasons, such as low cost of production. With these features, there are different areas of use other than the use of gas sensors. In this study, the usability of BNNT structures loaded with Au, Ag and Cu metal atoms for ethylene oxide adsorption and gas sensor was examined with Density Functional Theory (DFT). DFT calculations were made using the WB97XD (including distribution) hybrid method, which takes into account the effects of change and correlation. Metal atoms are charged to both B and N atoms of BNNT. After ethylene oxide adsorption, all of the adsorption energies were calculated as negative values in the structures. Adsorption energy and adsorption enthalpy values reached -25.2 kcal/mol and -8.2 kcal/mol, respectively. It has been observed that adsorption reactions can occur spontaneously on structures. Charge transfer from ethylene oxide molecule to BNNT structures has occurred.As a result of RDG analysis, the green colors formed on the map show Van der Waals interactions in the regions close to zero in the distribution maps. In line with this information, when the maps are examined, the effect of Van der Waals interactions in EO-adsorbed BNNT structures can be mentioned.In general, it has been observed that structures with metal atoms charged instead of N atoms work much better than structures with doped structures instead of B atoms. After all; The Au-doped BNNT can be used as both an electronic and work-function type gas sensor for ethylene oxide molecule at roomtemperature.