摘要
应用原位漫反射红外-质谱联用、程序升温和暂态响应技术研究了CuO/Al2O3催化剂表面酸性及其反应性能.实验结果表明,CuO/Al2O3催化剂表面呈Lewis酸性,硫化不仅可增强CuO/Al2O3催化剂的Lewis酸性,而且可产生新的Brφnsted酸性位;吸附于Lewis酸性位的NH3具有选择性催化还原(SCR)活性.而在硫化样Cu8(400S)中Lewis和Brφnsted酸性位同时存在的情况下,吸附于Lewis和Brφnsted酸性位的氨均具有SCR活性,且后者较前者弱;CuO/Al2O3催化剂上的SCR反应遵循Eley-Rideal机理,即SCR反应发生于吸附态NH3与气相NO之间.
Combined in situ diffuse reflectance FTIR （DRIFT） and on-line mass spectroscopy, temperature-programmed and transient experiments were performed to evaluate the surface acidity and reactivity of a CuO/Al2O3 catalyst. The results show that only ammonia coordinated at Lewis acid sites was found on the CuO/Al2O3 catalyst. Sulfation of CuO/Al2O3 catalyst greatly increases the concentration and strength of the Lewis acid sites and the concentration of BrФnsted acid sites. Ammonia adsorbed both on Lewis acid sites and BrФnsted acid sites plays an important role in the selective catalytic reduction of NO over the CuO/Al2O3 catalyst-sorbents, which occurs between the adsorbed ammonia and gaseous NO, following an Eley-Rideal mechanism.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2008年第9期1021-1027,共7页
Acta Chimica Sinica
基金
国家高技术研究发展计划(863,No.2002AA529110)
国家自然科学基金(No.20276078)资助项目
