Structure and activity of Ni/La_0.7Sr_0.3AlO _3-δ catalyst for hydrogen production by steam reforming of toluene

We investigated catalytic steam reforming of aromatic hydrocarbon using toluene as a model compound. Ni/La_0.7Sr_0.3AlO _3-δ catalyst showed high catalytic activity and low coke formation. Although the lattice oxygen in a perovskite-type support plays an important role for oxidizing CH_x and coke precursor, the role of interaction between Ni and the support has not been clarified. In this study, Ni/La_0.7Sr_0.3AlO_3-δ catalyst calcined at various temperatures (1073, 1173, 1273 and 1373 K) was prepared and used to elucidate the effect of Ni particle size on the lattice oxygen mobility. The Ni particle size increased concomitantly with increased calcination temperature, and the C₁ yield decreased from 72.9 to 15.5%. Enhancement of lattice oxygen mobility by the decrease of Ni particle size was observed by transient response tests using H₂¹⁸O over Ni/La_0.7Sr _0.3AlO_3-δ calcined at various temperatures. The interface between Ni and perovskite support played an important role for oxidizing coke precursor by lattice oxygen.