Simulation of the interaction of NiO with a graphene layer in a NiO$_x$/CNT composite based on XANES spectroscopy

The interaction of NiO clusters with a graphene layer of a nanotube in NiO$_x$/CNT composites is simulated based on a theoretical analysis of Ni K-edge XANES spectra. Various cases of orientation of crystallographic planes relative to the nanotube wall are considered. It was determined that Ni in the composite is predominantly in the 2+ state, NiO particles are oriented towards the tube wall by the (200) plane. Accounting for carbon atoms even in the first sphere of the nickel environment makes it possible to achieve good agreement between the theoretical spectrum and experiment.