Flame Pyrolysis Synthesis of Mixed Oxides for Glycerol Steam Reforming

Flame spray pyrolysis was used to produce nanosized Ni-based catalysts starting from different mixed oxides. LaNiO₃ and CeNiO₃ were used as base materials and the formulation was varied by mixing them or incorporating variable amounts of ZrO₂ or SrO during the synthesis. The catalysts were tested for the steam reforming of glycerol. One of the key problems for this application is the resistance to deactivation by sintering and coking, which may be increased by (1) improving Ni dispersion through the production of a Ni-La or Ni-Ce mixed oxide precursor, and then reduced; (2) using an oxide as ZrO₂, which established a strong interaction with Ni and possesses high thermal resistance; (3) decreasing the surface acidity of ZrO₂ through a basic promoter/support, such as La₂O₃; and (4) adding a promoter/support with very high oxygen mobility such as CeO₂. A further key feature is the use of a high temperature synthesis, such as flame spray pyrolysis, to improve the overall thermal resistance of the oxides. These strategies proved effective to obtain active and stable catalysts at least for 20 h on stream with very limited coke formation.