Carbon Monoxide-Defective Graphenes Adsorption Properties Investigation

With the rapid progress of correlation theory and numerical methods, density functional theory based on first-principles has get extensive attention in condensed matter physics, quantum chemistry and material science, being the vital theoretical foundation of computational science. Due to the unique microstructure, electronic structure and physicochemical property, graphene has been widely used in solar cells, gas sensors,composite materials and energy storage, etc., becoming the research highlight.In this paper, based on the first-principles method of density functional theory, we investigate the adsorption properties of CO on pristine, B/N-doped, vacancy graphenes and pristine, Li-doped, vacancy, Li-doped vacancy graphenes using the DMol3 and CASTEP module, respectively. The results from DMol3 calculation demonstrate that, compared with pristine, N-doped and vacancy graphenes, B-doped graphene has the largeest adsorption energy and charge transfer, which is one order of magnitude larger than others, and the greatest reaction towards the adsorption of CO. CASTEP module has improved the calculation precision and calculation process.The results illustrate that Li doping could enhance CO adsorption ability of pristine graphene and vacancy graphene. The adsorption energies of Li-doped graphene and Li-doped vacancy graphene are one order magnitude larger than that of pristine and vacancy graphene; the most charge transfer(0.13e) and the shortest distance(2?) are also occurred in these graphenes. From the results of band structures, density of states, partial density of states and electron density different, the electronic structures of Li-doped graphene and Li-doped vacancy graphene after CO adsorption are different a lot from that before CO adsorption, which means that the adsorption of CO can largely enhance the conductivity of these graphenes. Both the calculation results show that P type doping could improve the CO adsorption ability of graphene, and this provides a new direction for gas sensors with high sensitivity.