Gas adsorption on graphene with different layers: A first-principles study

At present, the sensor is widely used and its types are varied, such as biosensor, gas sensor, humidity sensor, optics sensor, pressure sensor, etc. However, many defects of sensors remain to be optimized in many aspects such as conductivity, stability and adsorption capacity. According to the performance of materials, the study of the adsorption behavior of H2, CO2, CH4, Ar and N2 on the pristine graphene has been performed through First-principle calculation. The graphene has been attracted popular attention all over the world, because the two-dimensional crystal structure of graphene has a good mechanical, electrical properties etc. The graphene also has a great specific surface area, so it has a well adsorption capacity. The graphene is a zero-n gap semiconductor with no magnetism, however, the graphene will be magnetic if it adsorbed or doped with other materials even the band gap is opened. Therefore, the graphene has a promising future in nano electronic devices such as gas sensor. We compared the electronic structures and the magnetism between the pristine graphene and the gas molecule-adsorbed graphene through the first principle calculation. We have found that the different types of graphene have different electronic band structures. Most of the molecules adsorption on graphene can be weakly charged took as donor or acceptor. We discovered that the band gap and the adsorption energy is different when the gas molecules adsorped on the graphene with different number of layers. The different layers have different impacts on the adsorption of graphene. Therefore, according to First principles calculation, with the number of layers increasing, the gas adsorption property of graphene is getting better and better. This study provides a rational way using first principle simulation to evaluate the different number of layers of graphene for the adsorption of sensors.