中文摘要：

采用共沉淀法制备了LaMnAl11O19六铝酸盐催化剂,采用XRD、BET和XPS对样品结构进行了表征,并通过模拟生物质气化气的燃烧实验和NH3单独氧化实验,分别考察了催化燃烧和均相燃烧过程中NH3的转化特性。利用原位漫反射红外光谱（in-situ DRIFT）法在线研究了NH3在催化剂表面的吸附和氧化信息。结果表明,焙烧后催化剂形成磁铅石（MP）结构的六铝酸盐晶体,且具有较大的比表面积,Mn以＋2、＋3价形式存在晶体中。均相燃烧下模拟气中的NH3在500℃开始反应,随之就有NO生成。催化燃烧工况下NH3氧化曲线和模拟气中NH3的转化曲线相差不大,NH3的起燃温度为310℃,反应后随之就有NO生成,NO在350℃～800℃保持一个较高的浓度。NO2的生成温度较高,并仅在较窄的温度区间内出现,在整个燃烧过程中仅检测到几个10-6的N2O,反应过程中有40%以上的NH3转化成NO。DRIFT结果表明,催化剂作用下NH3的转化遵循-NH反应机理,即催化剂表面吸附的NH3分解产生-NH,-NH与氧原子（O）反应生成HNO,再进一步反应生成N2或N2O,或是-NH直接与氧分子（O2）反应生成NO。

英文摘要：

LaMnAl11O19 catalysts were prepared by co-precipitation method and characterized with XRD,BET and XPS.The conversion of NH3 at the conditions of catalytic combustion and homogeneous combustion were studied by combustion of simulated biomass gasification gas and NH3 oxidation,respectively.Moreover,the NH3 adsorption and oxidation on the surfaces of the catalyst samples were examined by in-situ DRIFT experiments.It was found that calcination of the percursors at 1 200 ℃ led to the formation of a final monophasic materials with MP structure and high surface area,while the Mn ions were either divalent or trivalent.Under homogeneous combustion condition,NH3 at simulated biomass gasification gas started to react at 500 ℃,then NO was formed.Under catalytic combustion condition,the curves of NH3 oxidation with and without addition of simulated gasification gas showed no obvious differences.NH3 started to react at 310 ℃,and NO exhibited higher concentration in the temperature range of 350 ℃~800 ℃.However,NO2 was generated at higher temperature within a narrow temperature range.The concentration of N2O during the reaction was less than 10 ×10-6.More than 40% of the NH3 converted to NO during the experiments.The results of in-situ DRIFT indicated that the reaction of ammonia conversion followed the imide（-NH） mechanism,that is,the ammonia adsorbed on the catalyst surface was decomposed to-NH firstly,then the-NH reacted with atomic oxygen（O） to further form nitroxyl（HNO） and N2 or nitrous oxide（N2O）,or-NH reacted with molecular O2 to produce nitric oxide（NO） directly.