Autoreduction of promoted Ni/γ-Al2O3 during autothermal reforming of methane

The addition of the noble metals Pt, Pd and Ir to the Ni/gamma-Al2O3 catalyst used in the autothermal reforming of methane was investigated, with the aim of making the reaction ignite without previous reduction of the catalyst with H-2. In TPR-CH4, the catalysts promoted with Pt and Ir chloride suffered reduction at temperatures lower than 500degreesC, while the urpromoted catalyst and those promoted by addition of PdCl2 did not suffer reduction. Pd promoted the reduction only when added as the nitrate. The catalytic tests of intermittent start-up, alternating with air flow, showed results consistent with those from the TPR-CH4. Pt- and Ir-promoted catalysts were active in all the start-ups, producing a great quantity of hydrogen, while the sample promoted via paladium chloride did not produce hydrogen in significant quantity, converting methane only to CO2 and water. The samples promoted via palladium nitrate were very active in autothermal reforming without previous reduction, producing a great quantity of hydrogen. (C) 2004 Elsevier B.V. All rights reserved.