Autothermal reforming of methane over Ni/γ-Al2O3 promoted with Pd: The effect of the Pd source in activity, temperature profile of reactor and in ignition

The effects of adding small amounts of palladium to Ni/γ-Al2O3 catalysts for the autothermal reforming of methane, in terms of activity, reducibility, capacity of repeated ignition and temperature profile of the reactor are described. The effect of different Pd sources was also studied. The Pd addition favors nickel reduction at lower temperatures. When the palladium is added as PdCl2 (PdNiAl-Cl) it exhibits a higher reduction temperature than when Pd(NO3)2 (PdNiAl-N) is used, an this can be attributed to the formation of PdxClyOz species. Palladium strongly increases the activity of the Ni catalyst in autothermal reforming of methane, which is proportional to an increase in metal surface area. The addition of palladium to the catalyst also leads to a flatter temperature profile through the catalytic bed in the autothermal reforming of methane, and this is assigned to the high surface metal area of the catalyst. Only PdNiAl-N catalyst catalyzes the autothermal reforming of methane without previous reduction, while the PdNiAl-Cl catalyst only catalyzes the methane combustion and the unpromoted catalyst was inactive.

The effect of adding small amounts of palladium to Ni/γ-Al2O3 catalysts for the autothermal reforming of methane is mainly the promotion of reduction of nickel. The promotion of the reduction increases the number of active sites available for steam reforming and oxidation of methane, allowing both reactions to occur simultaneously.Figure optionsDownload as PowerPoint slide