Sustainable Ru-doped Ni catalyst derived from hydrotalcite in propane reforming

Trace amount of Ru-doped Ni/Mg(Al)O catalyst was prepared from hydrotalcite precursor and was tested in the reforming of propane under daily start-up and shut-down (DSS) operation. Mg(Ni,Al)O periclase derived from the hydrotalcite was dispersed in an aqueous solution of Ru nitrate, followed by calcination and reduction. Finely dispersed Ni–Ru was supported on Mg(Al)O periclase particles. The activity as well as the sustainability in the propane reforming was compared with the commercial Al2O3-supported Ni and Ru catalysts. The DSS operations of partial oxidation, steam reforming and autothermal reforming were carried out under steam or air purging conditions. The Ru doping suppressed the surface oxidation of Ni particles on the Ni/Mg(Al)O catalyst, resulting in the high activity as well as the high sustainability in all reforming reactions except under steam–air combined purging. The deactivation was effectively suppressed by increasing either reaction temperature or Ru doping even under steam–air combined purging. Ni particles also suffered by sintering, but the sintered Ni particles were redispersed and the activity was sustained during DSS operations. Air-purged partial oxidation was the most effective for the redispersion of the sintered Ni particles. This likely indicates that the finely dispersed Ni particles were continuously regenerated by reversible reduction–oxidation between Ni0 and Ni2+ via Mg(Ni)Al periclase assisted by hydrogen spillover from Ru or NiRu alloy.