Single atom adsorption on the WTe 2 monolayer is the most energetically favourable, followed by adsorption on WS 2 and then WSe 2 . The exception being that the X adsorption is strongest on WS 2 , followed by WTe 2 and WSe 2 . It should be noted however, that the difference in stability between the three monolayers is not significant, with a typical magnitude of ∼0.10 eV.