摘要
利用密度泛函理论和原子簇模型,对NH3和H2O分子在选择性催化还原(SCR)脱硝催化剂表面不同吸附位上的吸附进行了研究.结果表明:NH3能吸附在V2O5表面的Lewis和Brφnsted酸位,但在后者吸附位上更稳定.当V2O5以多聚物结构存在时,NH3能与O(1)H生成稳定的NH4+,该物质在SCR反应中起着关键作用,吸附能为-128 kJ.mol-1;同时水也可与该吸附位形成稳定构型,吸附能为-97 kJ.mol-1.在V2O5表面,水与NH3的吸附能相当,两者发生竞争吸附,从而在一定程度上对SCR脱硝反应产生抑制作用.
The adsorption of NH3 and H2O on different sites of denitrification catalyst has been studied with the density functional theory and cluster model.The calculated results indicate that ammonia adsorption takes place on both the Lewis and BrФnsted sites of V2O5 surface,whereas the adsorption on the BrФnsted sites is found to be more favorable energetically.NH4^＋ specie,which plays an important role in SCR reaction,forms on O（1）H site of polymeric species with-128 kJ·mol^-1.Water can adsorb at the same site stably with-97 kJ·mol^-1.On the V2O5 surface,adsorption energy of water is the same as ammonia.Competitive adsorption of water and ammonia restrains the SCR reaction.
出处
《环境化学》
CAS
CSCD
北大核心
2008年第1期33-38,共6页
Environmental Chemistry
关键词
密度泛函理论
吸附
五氧化二钒
氨
水
density functional theory,adsorption,vanadium oxide,ammonia,water.
