Strong Metal-Support Interactions of TiN- and TiO2-Nickel Nanocomposite Catalysts

This study investigates the electronic configuration of titanium nitride-nickel (TiN-Ni) nanocomposites, in order to explain the high stability and activity of this hydrogenolysis catalyst. TiN-Ni is compared to a titanium oxide-nickel reference (TiO2-Ni). Strong metal support interactions are observed between the TiN and Ni. Scanning transmission electron microscopy (STEM) and energy-dispersive X-ray spectroscopy (EDS) illustrate that the Ni distributes more homogeneously on the nitride support. Computational comparison of TiN Ni and TiO2-Ni provides evidence of preferential Ni adsorption onto nitrogen sites of the nitride support. DFT calculations also predict a charge polarization between Ti and Ni atoms. X-ray photoelectron spectroscopy (XPS) corroborates computational analysis by revealing a suppression of surface nitride species upon deposition of Ni onto TiN. Shifts in Ti 2p and Ni 2p binding energy positions are also evident, which indicate an electronic perturbation between TiN and Ni. We conclude that the presence of nitrogen in the nitride support influences the electronic and structural properties of TiN-Ni and is partly responsible for the beneficial catalytic properties reported for this nanocomposite.