Metal grids with high-porous surface as structured catalysts: preparation, characterization and activity in propane total oxidation

Metal nickel and copper grids are shown to be suitable supports for structured combustion catalysts. The increase of specific surface area (SSA) of metal grids was achieved due to the porous outer layer with the structure of Raney metal developed on the wire surface. Transition metals (Co, Cu, Mn, Cr) oxides were deposited as active components on the pre-oxidized support and tested in total propane oxidation. Cobalt oxide demonstrated the highest activity. Reductive pre-treatment in the flow of hydrogen resulted in a more active catalyst than the activation in oxygen atmosphere. This effect was assigned to the partial reduction of Co3O4 until metallic Co, which was detected by XPS on the catalyst surface. Deactivation of the pre-reduced Co-oxide catalyst was observed during propane combustion in excess of oxygen and was ascribed to the oxidation of partially reduced active phase. After 4 h on stream, the catalyst reached his steady-state and showed stable activity without further deactivation. The catalytic activity expressed in the terms of propane conversion was observed to depend on the propane/oxygen ratio.