Mn-doped covalent organic framework (COF), graphene, and their nanocomposite (Mn@GP/COF) as sensors for oil-dissolved gases in transformer: A computational study

All things being equal! As gas pollutants continue to pose threat to life so is the emergence of sensor devices that detect and capture these gases. Herein, two of the oil-decomposed gases (C2H4 and CO) in an oil-immersed power transformer were adsorbed to examine the sensor performances of Mn-doped covalent organic framework (Mn@COF) and that of graphene (Mn@GP), as well as their nanocomposite (Mn@GP/COF). This investigation was carried out using the first principle within density functional theory (DFT), with the ωB97XD/6–311 G(d,p)/LanL2DZ method. The most negative adsorption energies are featured in the adsorption of C2H4 and CO gas molecules on Mn@GP/COF nanocomposite, showing that the gases are best adsorbed on Mn@GP/COF as compared to Mn@COF and Mn@GP surfaces. Due to the least energy gap of 0.272 eV, the CO_Mn@GP/COF complex is the most stable. Relatively small energy gap of 0.77 eV was observed in C2H4_Mn@GP/COF, indicating stability during C2H4 gas adsorption. In most cases, non-covalent nature of interactions was observed, coupled with a van der Waals interaction. In all, greater tendency to move toward, interact, and keep to the adsorbent was ascertained by the Molecular dynamic simulation. Hence, the inherent sensing ability of Mn@GP/COF nanocomposite revealed in this research would be beneficial to experimental researcher in choosing the surface as a promising candidate in engineering gas sensor devices.