Enhancing performance of Ni/La2O3 catalyst by Sr-modification for steam reforming of toluene as model compound of biomass tar

Steam reforming of biomass tar with toluene as the model compound was studied using Sr-doped Ni/La2O3 catalysts prepared using two methods, i.e. co-impregnation of Sr and Ni on La2O3 support (Ni-Sr/La2O3 catalyst) and sequential impregnation of Sr on Ni/La2O3 catalyst (SNL catalyst), which were then calcined at various temperatures (500, 700, and 900 degrees C). These two types of catalysts are found to possess better catalytic performance than the undoped Ni/La2O3 catalyst at the same calcination temperature due to the presence of Sr, which helps in water adsorption at low steam/carbon (S/C) ratio. Moreover, the catalytic performance for catalysts calcined at various temperatures decreases following this trend: 500 degrees C > 700 degrees C > 900 degrees C due to lower BET surface area and lower surface active metal available for reaction. In addition, it is also observed that the Sr/Ni/La2O3 catalyst has better performance than the Ni-Sr/La2O3 catalyst at the same calcination temperature. Further characterization results suggest that in the Ni-Sr/La2O3 catalyst, the Sr is present between Ni and La2O3 support. On the other hand, Sr in the Sr/Ni/La2O3 catalyst is thought to be located on the surface of Ni/La2O3 due to the preparation method. This study shows that more Sr on the catalyst surface has better catalytic activity and stability in steam reforming of toluene.