Adsorption behaviors of CO, H2O, CH4, H2S, H2 and NH3 gases on Cu-doped MoO3 monolayer: A first-principles study

Abstract

Carbon monoxide (CO) is an odorless, colorless and highly toxic gas, developing gas sensor with high sesitivity toward CO gas is critical for controlling combustion processes. In this paper, the characteristics of adsorption of CO, H2O, CH4, H2S, H2 and NH3 gases on Cu-doped MnO3 are investigated by first-principles calculations. The adsorption of CO on Cu-MoO3 shows the highest adsorption energy together with the largest differential charge density, indicating a strong interaction between CO and Cu-MoO3. The strong interaction is also demonstrated by the smallest adsorption distance of 1.526 Å between Cu-MoO3 and CO molecules. Moreover, the DOS of the system with the incorporation of CO moves to the lower energy levels and the DOS near the Fermi energy level increases, which will lead to significant change in conductivity of Cu-MoO3. It can be inferred that Cu-MoO3 show high sensitivity and selectivity toward CO gas.