Enhanced NOx adsorption and sensing properties of MoTe2 monolayer by Ni-doping: A first-principles study

Based on the first-principles theory, we studied the adsorption behavior of pristine and Ni-doped MoTe2 (Ni-MoTe2) monolayer towards NOx, in order to explore their potentials to be a resistance-type chemical gas sensor. Firstly, we studied the geometric and electronic behaviors of Ni-doping on MoTe2 monolayer, which shows that Ni dopant could be stably adsorbed on the MoTe2 monolayer through the T-Mo site, causing enhanced electron density and reduced energy gap as well. For adsorption of NOx, Ni-MoTe2 monolayer behaved better performance compared with intrinsic counterpart, due to the pronounced electron hybridization between Ni dopant and gas molecules, leading to larger adsorption energy and charge transfer accordingly. Besides, the adsorption of NOx brought about more remarkable change in the bandgap of Ni-MoTe2 monolayer than that of intrinsic MoTe2 monolayer, exhibiting stronger potential for Ni-MoTe2 monolayer to be explored as NOx sensors or adsorbent. This work would be beneficial to extend the application of TMDs as chemical gas sensors applied in the fields of environmental monitoring and industrial manufacturing.