M2cs2 (M = Sc, Y) with Brand-New Mxene Phase: The Promising Candidate as the N/O-Containing Gases Sensor And/Or Capturer

Abstract

Recent experimental work (Science, 2020, 369, 979) reported the successful synthesis of S-terminated MXenes, among which the M2CS2 (M = Sc or Y) exhibits the brand-new phase vary from all the already known MXenes. In this work, we have theoretically studied the adsorption of 17 kinds of gases (including atmospheric and organic molecules) on M2CS2. Our results revealed that M2CS2 prefers to interact with the N/O-containing gases by forming M–N/M–O bond. Among all the gases, the NH3 and nicotine could be captured by M2CS2 in view of their low adsorption energies (< -0.50 eV). By considering the changes in charge transfers, electronic properties and current/voltage curves before and after the gas adsorption, we proposed that Sc2CS2 could be the potential candidate as NO, NO2, NH3, nicotine, ethanol and formaldehyde gas sensors with high sensitivity and selectivity. It is noted that the Sc2CS2 is reusable after gas sensing or capturing in view of their moderate adsorption energies (> -0.60 eV). The above features in Sc2CS2 are also expected in the case of Y2CS2, in view of their similar chemical properties. Our results will be very helpful for understanding the chemical properties and the potential applications of this unique MXene phase (M2CS2).

Keywords: S-terminated MXenes, Gas sensor and capturer, 2D materials, gas adsorption, First-principles simulation