摘要
采用密度泛函理论(DFT)方法研究了NO和NH3在完整和有缺陷的γ-Al2O3(110)表面吸附与SCR(选择催化还原)反应特性。研究表明,NO在完整的(110)表面的吸附作用较弱,而NH3分子的吸附作用较强,NH3分子在Al原子顶位可形成稳定吸附。反应路径研究结果表明完整的(110)表面上SCR反应的决速步为—NH2NO基团的分解,反应的最大能垒为235.75 kJ·mol-1。对于产生氧空穴的有缺陷(110)表面,NO和NH3均可稳定吸附,NH3在吸附过程中可直接裂解成NH2和H。另外,SCR反应在有缺陷(110)表面的最大能垒明显较低,说明氧空穴的存在促进了SCR脱硝反应的进行。
γ-Al2O3is an outstanding catalyst carrier and has been widely used in the SCR （selective catalytic reduction） catalyst study. The adsorption and reaction properties of NO/NH3 on the bare and defectiveγ-Al2O3 （110） surface were studied by the DFT （density functional theory） method. The corresponding microscopic parameters, such as adsorption energies, bond length, changes of net charge and PDOS （partial density of states） were calculated. NO could be adsorbed on the bare （110） surface weakly, and it was more inclined to be adsorbed on the top sites of O2c. NH3 could be adsorbed strongly on top sites of Al. The rate-determining step of SCR reaction was the-NH2NO decomposition, while the largest energy barrier reached 235.75 kJ·mol^-1. For the defective （110） surface with the oxygen vacancy, NO and NH3 could be both adsorbed strongly on the surface, and NH3 could also decompose into NH2 and H directly in this situation. The largest energy barrier of SCR reaction in this situation was much lower, indicating that the presence of oxygen vacancy could promote SCR reaction proceeding.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2014年第10期4056-4062,共7页
CIESC Journal
基金
教育部科学技术研究项目(113045A)
国家自然科学基金项目(51176062
51306046)~~
关键词
氧化铝
分子模拟
吸附
密度泛函
一氧化氮
alumina
molecular simulation
adsorption
density functional theory
nitric oxide
