CO₂-reforming of CH₄ to syngas over Ni-based catalyst

The surface features and catalytic performance of Ni-based catalysts for CO₂-reforming of CH₄ to syngas were investigated by TPR, XRD and catalytic performance evaluation. It was found that the optimal Ni content of Ni-based catalysts was about 9. 0%. As Ni content increased beyond this limit, NiO crystal particles formed over catalyst made no contribution to the catalytic performance, which probably was due to carbon deposition. The results of TPR, XRD and catalytic test of Ni/Al₂O₃ catalyst prepared by impregnation method indicated that the lower the calcination temperature was, the more the highly dispersed nickel oxide species which were reducible produced and the higher the catalytic activity was. It was also found that the promoters and supports had pronounced influence on the catalytic performance of Ni-based catalysts. MgO and La₂O₃ doped Ni/Al₂O₃ catalyst could markedly improve its reaction stability as well as its resistance to carbon deposition. Ni/MgO catalyst exhibited excellent reaction stability without decay in catalytic activity for 100 h duration at 750 C. According to the XRD results of these catalysts (fresh, reduced, and after stability test), the excellent catalytic performance, which Ni-MgO-La₂O₃/Al₂O₃ and Ni/MgO catalysts exhibited, was attributed to the high dispersion and stability of tiny metallic nickel crystal particles.