Catalysis Today, Vol.131, No.1-4, 444-449, 2008
Promotion effect of cerium and lanthanum oxides on Ni/SBA-15 catalyst for ammonia decomposition
CeNi/SBA-15 and LaNi/SBA-15 catalysts were prepared by deposition-precipitation (DP) method and characterized by N-2 physical adsorption, XRD, H-2-TPR, H-2-chemisorption and TEM. Their catalytic performances in the ammonia decomposition reaction were tested and compared with Ni/SBA-15 catalyst. Addition of cerium and lanthanum oxides to the Ni/SBA-15 catalyst caused some decrease of BET surface area and pore volume of the catalysts, but led to a promotion effect to their catalytic activity which was closely related to the ratio of Cc (La)/Ni. The highest conversion of ammonia could be obtained when the Ce (La)/Ni ratio was around 0.3. The promotion effect is more evident on CeNi/ SBA-15(0.3) than on LaNi/SBA-15(0.3) catalyst under identical reaction conditions. The CeNi/SBA-15 and LaNi/SBA-15 catalysts show smaller nickel particle size and easier reducibility in comparison with the Ni/SBA-15 catalysts. (C) 2007 Elsevier B.V. All rights reserved.