Effect of Magnetic Inducement in Preparation of Ni/Ce- doped Al O for Ammonia Decomposition

摘要

Catalytic activity of Ni catalysts for NH3 decomposition can be enhanced by using Ce-doped Al2O3 support. Magnetic induce- ment during sol-gel preparation of supports was studied to enhance the Ce dispersion in Al2O3 framework. In this study, the same poles and different pole of magnetic arrangement were applied during the sol-gel preparation. Ni catalysts over the supports were investigated for the NH3 decomposition activity along with catalyst and support properties, including Ce dispersion in Al2O3 framework, Ni dispersion, acidic sites, basic sites, and reaction kinetics. The magnetic inducement can control the Ce composition and uniformity in the Al2O3 framework. The Ni/Ce-doped Al2O3 prepared under the same poles of magnetic inducement show significant improvements in Ni dispersion, and yield highest catalytic activity due to a high Ce composition and uniformity in the framework, as well as the high Lewis basic sites which enhance the limiting step of NH3 decomposition. Thus, combination of the partial doping with magnetic inducement provides a novel approach with low cost to improve the activity of Ni catalyst without changing the reaction mechanism.