Effect Of Doping Modification And Carrier For Nickel-Based Perovskite Catalyst On Ammonia Decomposition

The hydrogen which have advantages of no pollution,reusable,mature preparation process and high combustion value,become a new energy’s first choice to replace fossil energy.Proton exchange membrane fuel cell（PEMFC）, uses hydrogen as a fuel, light quality, high efficiency,has potential application prospect in the respect of power supply in electric cars and all kinds of mobile equipment.Ammonia decomposition can produce high purity hydrogen,without CO by-products,simple process,low cost, make it suitable for proton exchange membrane fuel cell（PEMFC）.However ammonia decomposition produce hydrogen has many disadvantages,such as high reaction temperature（completely reaction temperature is 700℃） and high catalyst price, affect the promotion of use.LaNiO₃ is perovskite（ABX₃） structure which has thermal stability, low cost, strong REDOX ability.As a catalyst in the ammonia decomposition produce hydrogen process, it can reduce the ammonia decomposition reaction temperature.In this study,we hope through the study of the modification of LaNiO₃, the reaction can has a lower temperature.The MCM-41 which was prepared by different expanding agent, use as a carrier for preparing a supported catalyst perovskite. Specific contents are as follows:First of all, we prepared a series of perovskite-type La_0.9X_0.1NiO₃（X = Li, Na, K, Ba） catalyst, using ammonia decomposition activity evaluation and TPR, XRD characterizations, select the best A-site doping elements and doping amount, the experiment results showed that the optimal doping elements was Ba, optimal doping amount was x = 0.1.Secondly, we change the preparation La_0.9Ba_0.1NiO₃ solvent（ethanol, methanol）,study the solvent affect the performance of the catalytic ammonia. It was found that catalyst which use an organic solvent have a single phase perovskite structure, and have a low the ammonia decomposition catalytic activity.The perfect lattice structure may reduce catalytic activity.Again, add the expanding agent（triethylamine, mesitylene, n-decane） in the synthesis of MCM-41 process. XRD, TEM, BET characterization results showed that triethylamine as expanding agent for preparing samples MCM-41 has regular mesoporous structure, pore volume and large surface area.The last, take basic and reaming type MCM-41,respectively,as the carrier, with La_0.9Ba_0.1NiO₃（w（NiO）=20%） as catalyst active component,we found on the carrier of MCM-41,ammonia conversion rate（100%） at 596℃. Comparing with non load La_0.9Ba_0.1NiO₃ activity,the complete decomposition of ammonia temperature can reduces around 50℃.