To investigate the impact of doping on the chemical activity of MoTe 2 , we have examined the adsorption of O 2 molecule on MoTe 2 and X-MoTe 2 . This selection was motivated by four factors: (i) the molecule's widespread use as a reagent , (ii) its moderate reactivity , (iii) its abundance in the atmosphere, (iv) its potential to influence the charge-carrier concentration of sensing layers in chemical sensors . Determining the lowest-energy configuration for adsorption on pristine surfaces of TMDs can be a challenging endeavor. This difficulty arises from the chemically inert nature of the surfaces and the typically weak vdW forces governing molecule-surface interactions. Consequently, molecules lack a well-defined adsorption site and adsorb on the surface in number of different position with low energy barrier between them. However, it should be noted that this is usually investigated to confirm the absence of chemisorption on the surface . In the case of doped sheets, the problem becomes somewhat less complex as it is reduced to the effects emerging in the vicinity of the doping site. Those, in turn, tend to enhance the molecule-sheet interactions, enabling better defined adsorption configurations. Consequently, in our case, the most suitable approach would be to employ the same initial adsorption geometries across all sheet to enable better illustration of effects facilitated by doping. Furthermore, given the simple structure of the oxygen molecule, it it sufficient for us to focus on just two initial configurations: horizontal (Figure ) and vertical (Figure ). Chosen geometries are localized, with one oxygen atom always directly above the doping site.