Partial oxidation of methane over a Ni/BaTiO3 catalyst prepared by solid phase crystallization

Ni/BaTiO3 catalyst has been prepared by solid phase crystallization (SPC) and used successfully for partial oxidation of CH4 into synthesis gas at 800 degrees C. In the SPC method, Ni/BaTiO3 catalyst is obtained in situ by the reaction of starting materials with nickel species homogeneously incorporated in the structure. For the starting reagents, materials of two compositional types were employed i.e., perovskite structures BaTi1-xNixO3-delta (0 less than or equal to x less than or equal to 0.4) and stoichiometric structures, BaTiO3, Ba2TiO4 and BaTi5O11, with 0.3 NiO. The starting materials were tested for oxidation of CH4 by increasing the reaction temperature from room temperature to 800 degrees C. The catalysts showed the highest activity for synthesis gas formation around 800 degrees C, and the highest value was obtained at a composition of x = 0.3 in the former catalysts. Among the latter catalysts, the highest activity was observed over BaTiO3 . 0.3NiO, which was more active than BaTi0.7Ni0.3O3-delta. On the both catalysts, nickel species originally incorporated in the structure were reduced to the metallic state during the reaction. The BaTio(3) . 0.3NiO catalyst was further tested for 75 hours at 800 degrees C with no observable degradation and negligible coke formation on the catalyst. Thus, Ni/BaTiO3 prepared in situ from the perovskite precursor, i.e., by the SPC method, was the most active and resistant to coke formation and deactivation during the reaction. This may be due to well, dispersed and stable Ni metal particles over the perovskite, where the nickel species thermally evolve from the cations homogeneously distributed inside an inert perovskite matrix as the precursor.