Given our approach and the scope of the study, we have examined 46 distinct structures, encompassing both horizontal and vertical configurations for each of the 23 substrates (comprising one pristine and 22 doped monolayers). That being said, in all of the investigated cases, our results have reveal that O 2 consistently favors a vertical orientation, even when substrates exhibit significant variations in their molecule-sheet interactions. This preference likely stems from combination of factors. Firstly, dispersive interactions will generally favor vertical alignment of O 2 , since it brings both oxygen atoms closer to the surface. Secondly, when molecule-sheet interactions assume a directional character, it is unlikely that they will adopt a linear coordination geometry. This is because the three lone pairs of oxygen do not align well with this configuration, thus promoting the bent bonding geometry in oxygen instead, which results in vertical orientation of the molecule.