Theoretical study of the adsorption and sensing properties of pure and metal doped C24N24 fullerene for its potential application as high-performance gas sensor

Abstract

Density functional theory (DFT) calculation was used to study the potential applications of pure and metal-doped C24N24 fullerene as highly sensitive and selective gas sensors. It is found that gases commonly existing in the air, including NO2, CO, NO, NH3, N2 and CO2, are weakly adsorbed on pure C24N24. The adsorption strength is increased when they are adsorbed on the metal-doped (Co-, Cr-, Cu-, K-, Li-, Fe-, Ni-, Pd-, Ti-, Mn-, Na-, Zn-, V-) C24N24. The pure and metal-doped C24N24 have a specific response to certain gas according to adsorption energy, charge transfer, band gap and the density of states analyses. Among various metal-doped C24N24, the adsorption energies of NO2 on K- and Na-doped C24N24 are apparently lager than those of other gas molecules, which fall between the suitable range of strong physical adsorption and weak chemical adsorption. Upon NO2 adsorption, the band gap changes of K- and Na-doped C24N24 which corelate with its conductivity reach −12.75% and −26.67%, respectively. In accordance with the band gap changes, the density of states changes and charge transfer for NO2 adsorption on K- and Na-doped C24N24 are most obvious. Sensor performance analysis further shows K- and Na-doped C24N24 are highly selective in NO2 detection. The recycle time of Na–C24N24 under ambient condition is also in the suitable range (1.80 s). This study concludes the potential application of the Na-doped C24N24 as high-performance NO2 sensor.