XAFS Study of MoS2 Intercalation Compounds

MoS2 intercalated with Mn, Co, Ni, and Ru species, prepared from single layer MoS2 dispersions in water, were studied by x-ray absorption spectroscopy. M. K-edge EXAFS results (M = Mn, Co, Ni) are consistent with an alternating MoS2-M(OH)2 layered structure. For the Mn and Co intercalates the MoS2 layers were found to be very similar to that of the parent crystalline MoS2 with trigonal prismatic coordination of the Mo atoms. For the Ni and Ru intercalates, Mo K edge EXAFS revealed structural rearrangement of MoS2 layers similar to that observed for MoS2 single layers, with octahedral coordination of Mo. S K edge XANES spectra reveal that the rearrangement is coupled with a change in the electronic structure of the S atoms in the matrix. 'Ihese changes can be associated with charge transfer between 'host' and 'guest' layers. In addition, SO42- and Mo6+ were detected in some of the intercalated materials, presumably due to exposure to air, suggesting that transition metal intercalation may increase the susceptibility of the MoS2 layers to oxidation