partial oxidation of methane to syngas on bulk nial2o4 catalyst. comparison with alumina supported nickel, platinum and rhodium catalysts

in this work the catalytic performance of nial₂o₄ catalyst in the partial oxidation of methane (ch₄(1)/o₂(0.5)/n₂(8.5) and 4800 ml ch₄ g⁻¹ h⁻¹) was investigated. this bulk catalyst resulted more active (70% conversion at 625 °c) than alumina supported nickel catalysts prepared by conventional impregnation (11%ni/al₂o₃-30% conversion at 625 °c and 14%ni/al₂o₃-65% conversion at 625 °c) and a commercial platinum catalyst (1%pt/al₂o₃-30% conversion at 625 °c). further, the behaviour of nial₂o₄ was comparable to that of a commercial rhodium catalyst (1%rh/al₂o₃-75% conversion at 625 °c). fresh and spent catalysts were characterised by n₂-physisorption, h₂-tpr, uv-vis-drs, wdxrf, xrd, tga-ms, tem and raman spectroscopy. after catalyst reduction ch₄ conversion over bulk nial₂o₄ was associated with the formation of large amounts of metallic nickel crystallites with a relatively small size. although significant coking was noticed, conversion and selectivity to h₂/co were not significantly affected after prolonged time on stream.