Controlling the Coke Formation in Dehydrogenation of Propane by Adding Nickel to Supported Gallium Oxide

Atomic layer deposition was applied on mesoporous silica to synthesize a highly dispersed gallium oxide catalyst. This system was used as starting material to investigate different loadings of nickel in the dehydrogenation of propane under industrially relevant, Oleflex-like conditions. The formation of NiGa alloys was confirmed by X-ray diffraction analysis and electron microscopy. Surprisingly, the nanoalloys enhanced the selectivity towards C3H6 while decreasing the tendency for coking. Herein, in situ thermogravimetry, and measured mass fractions of carbon revealed that the coking rate was reduced by over 50 % compared to the pristine gallium oxide. Generally, the increased selectivity can be explained by the partial hydrogenation and reduction of the gallium oxide surface. The optimum temperature for the removal of deposited carbon was evaluated by a temperature programmed oxidation. Finally, the best-performing Ni-GaOx catalyst was employed in a cycled experiment with periodic reaction and regeneration tests. After regeneration, the selected Ni-GaOx catalyst provided a higher yield of propylene compared to the unmodified gallium oxide. A supported gallium oxide catalyst, synthesized by atomic layer deposition, was modified by the addition of nickel, and used in the dehydrogenation of propane. Resulting NiGa nanoparticles helped to reduce the coke formation on gallium oxide under industrially relevant conditions. Finally, the catalyst system could be regenerated by an oxidative treatment.image