Enhanced adsorption of CO on B, N, Ni co-doped graphene: A first-principles study

With the increasingly serious environmental pollution, it is of great significance for gas sensors to detect and adsorb harmful gases. Doping modified graphene as a toxic gas sensor has been widely studied in recent years. The adsorptions of B-doped graphene (B-G), N-doped graphene (N-G), Ni-doped graphene (Ni-G), B-Ni co-doped graphene (B-Ni-G), and N-Ni co-doped graphene (N-Ni-G) toward the toxic gas CO have been studied using firstprinciples calculations. The adsorption configuration, charge transfer, electronic properties, sensitivity and recovery time of CO on single doped graphene systems and co-doped graphene systems are discussed in detail. It is found that CO is weakly adsorbed on B-G and N-G with a high adsorption energy, while Ni-G has a relatively enhanced adsorption energy toward CO. Compared to single doped graphene, N-Ni-G exhibits stronger adsorption toward CO with lower adsorption energy than other substrates. The results show that CO adsorption on the co-doped graphene can enhance the conductivity of the structure due to the change of electronic properties. The theoretical recovery time is also calculated to estimate the reusability of the substrate in gas sensing. The N-Ni-G exhibits stronger interaction with CO than B-Ni-G, and N-Ni-G (ortho) is more likely to serve as a promising and efficient CO gas sensing material.