DFT模拟VPO/TiO_(2)催化剂表面NO和NH_(3)吸附的研究  

Study on adsorption of NO and NH_(3)on VPO/TiO_(2) catalysts by DFT simulation

作　　者：黎柳升 徐彬 张铭 张佳豪 陈雅芬 宋慈 郭丽娜 春铁军 贾勇 LI Liusheng;XU Bin;ZHANG Ming;ZHANG Jiahao;CHEN Yafen;SONG Ci;GUO Lina;CHUN Tiejun;JIA Yong(Guangxi Iron&Steel Group Co.,Ltd.,Fangchenggang 538000,China;School of Energy and Environment,Anhui University of Technology,Ma′anshan 243002,China;School of Metallurgical Engineering,Anhui University of Technology,Ma′anshan 243002,China)

机构地区：[1]广西钢铁集团有限公司,广西防城港538000 [2]安徽工业大学能源与环境学院,安徽马鞍山243002 [3]安徽工业大学冶金工程学院,安徽马鞍山243002

出　　处：《能源环境保护》2023年第4期140-148,共9页Energy Environmental Protection

基　　金：安徽省自然科学基金项目(KJ2019A0079,KJ2020A0236)。

摘　　要：氮氧化物(NO_(x))作为主要大气污染物之一,严重影响环境安全和人类健康。选择性催化还原法(NH_(3)-SCR)是目前脱除NO_(x)最有效的治理方法,尤其是低温SCR脱硝技术具有非常重要的应用前景和研究意义。研究表明VPO/TiO_(2)催化剂具有优异的低温SCR脱硝活性,本文通过DFT模拟NH_(3)和NO在V_(2)O_(5)和(VO)_(2)P_(2)O_(7)表面的吸附,对VPO催化剂的反应机理进行了微观层面上的研究。研究表明NH_(3)在V_(4)P_(4)O_(22)H_(14)团簇表面的Br nsted酸和Lewis酸都发生稳定的化学吸附,在Br nsted酸位点吸附更稳定,并且NH_(3)在催化剂表面吸附效果佳是因为N的2p轨道和O的2p、V的3d电子轨道能发生了杂化。NO在V_(4)P_(4)O_(22)H_(14)团簇表面也是化学吸附,由于电子转移量较小,显著低于NH_(3)的吸附能,并不能和NH_(3)分子产生强烈竞争,另外NO在V_(6)O_(20)H_(10)团簇表面的Br nsted酸和Lewis酸均发生稳定的化学吸附,且在Br nsted酸位点吸附更稳定。说明了VPO/TiO_(2)催化剂反应机理中的E-R机理和L-H机理。Nitrogen oxides(NO_(x)),as one of the main atmospheric pollutants,seriously affect environmental safety and human health.Selective catalytic reduction(NH_(3)-SCR)is the most effective treatment method for NO_(x)removal at present,especially low-temperature SCR denitrification technology,which has very important application prospects and research significance.The research showed that VPO/TiO_(2)catalyst had excellent low-temperature SCR denitrification activity.The adsorption of NH_(3)and NO on V_(2)O_(5)and(VO)_(2)P_(2)O_(7)surface was simulated by DFT,and the reaction mechanism of VPO catalyst was studied at the micro level.The results showed that NH_(3)exhibited stable chemisorption of Br nsted acid and Lewis acid on the surface of V_(4)P_(4)O_(22)H_(14)cluster,and the adsorption effect on Br nsted acid sites was more stable.NH_(3)adsorption effect on the surface of catalyst was excellent because of the hybridization of 2p orbital of N,2p of O,and 3d electron orbital of V.NO also showed chemisorption on the surface of V_(4)P_(4)O_(22)H_(14)cluster.Due to the small amount of electron transfer,which was significantly lower than the adsorption energy of NH_(3),NO could not strongly compete with NH_(3)molecule.In addition,NO showed stable chemisorption on Br nsted acid and Lewis acid on the surface of V_(6)O_(20)H_(10)cluster.The adsorption on Br nsted acid sites was more stable.The E-R mechanism and L-H mechanism of VPO/TiO_(2)catalyst reaction mechanism were explained.

关 键 词：DFT模拟 SCR脱硝 VPO 反应机理 

分 类 号：X701[环境科学与工程—环境工程]