Effect of preparation method on structural characteristics and propane steam reforming performance of Ni-Al2O3 catalysts

Propane steam reforming was studied over Ni-Al2O3 catalysts that were prepared by a conventional impregnation (IM) method and a one-step sol-gel (SG) technique. Both Ni-Al2O3 catalysts showed similar initial activity. However, IM-Ni-Al2O3 deactivated severely with time-on-stream of propane steam reforming. The catalyst prepared using a SG technique demonstrated stable catalytic performance. The two catalysts also showed major differences in product distribution, with SG catalyst giving much higher yields of hydrogen. Catalysts were characterized with temperature-programmed reduction (TPR), Xray photoelectron spectroscopy (XPS), temperature-programmed oxidation (TPO). transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy. It was revealed that, with sol-gel preparation, highly dispersed small Ni crystallites are formed with a strong interaction with the support. This is shown to be important for coke suppression and catalyst stability. (C) 2008 Elsevier B.V. All rights reserved.