Effect of catalyst structure on steam reforming of toluene over Ni/La_0.7Sr_0.3AlO_3-δ catalyst

We investigated steam reforming of toluene as a biomass tar model on Ni/La_0.7Sr_0.3AlO_3-δ, which has high activity and low carbon deposition for hydrogen production. Carbon deposition was suppressed by the oxidation of surface carbon species with lattice oxygen on support. The effects of Ni particle size and support surface area on catalytic features were evaluated by varying the calcination temperature of supported Ni and perovskite support independently. Activity tests, isotopic transient response tests, and characterization were performed to ascertain how interaction between Ni and support contributes to this reaction. Additionally, we evaluated the catalytic activity and carbon deposition per unit of Ni surface and perimeter. The lattice oxygen release rate depends on the specific surface area of the support, Ni-support interface, and catalyst structure. High surface area of the support accelerates the exchange of lattice oxygen through the redox cycle during steam reforming. Furthermore, the larger interface between Ni and support enables rapid lattice oxygen release. When the lattice oxygen release rate was higher, the catalytic activity was higher and carbon deposition was lower for each catalyst. These results confirm that lattice oxygen plays an important role in the activation of toluene and removal of carbon deposition on supported Ni.