Adsorption and sensing performances of air decomposition components (CO, NOx) on Cr modified graphene surface

Abstract

The adsorption and sensing abilities of air decomposition components such as CO, NO, and NO2 on a Cr-graphene monolayer were investigated using the first principles of density functional theory. Firstly, three possible doping points of Cr atoms on the surface of graphene were studied, and the most stable Cr-graphene monolayer was obtained through modeling and computational analysis. Then, various adsorption structures were constructed and optimized based on the model. The most stable adsorption structure of Cr-graphene monolayer for the three characteristic gases was determined by comparing their adsorption energy and other relevant parameters.Furthermore, state density, differential charge, and molecular orbital theory analyze the gas sensing mechanism and desorption time. The results show that the surface of the pristine graphene has a weak adsorption effect on these gases, and the Cr-graphene monolayer has good adsorption performance for the three gases. Although the calculation results show that Cr-graphene monolayer has strong adsorption and gas sensitivity performance for the three components, the recovery performance of the Cr-graphene monolayer needs to be improved because of the immense adsorption energy of Cr-graphene monolayer for the three components. The calculation can provide a theoretical guidance for gas sensors based on graphene and its modified materials.