钒磷氧催化剂表面酸性位特性及低温脱硝性能研究  

Characteristics of surface acidity site and low temperature denitrification performance of VPO catalysts

作　　者：荣卫龙 余洁 张嘉琪 屈晨曦 支盈盈 郭丽娜 贾勇 RONG Weilong;YU Jie;ZHANG Jiaqi;QU Chenxi;ZHI Yingying;GUO Lina;JIA Yong(Shandong Air Environmental Protection Science&Technology Co.,Ltd.,Zibo Shandong 256400;School of Energy and Environment,Anhui University of Technology,Ma’anshan Anhui 243002)

机构地区：[1]山东爱亿普环保科技股份有限公司,山东淄博256400 [2]安徽工业大学能源与环境学院,安徽马鞍山243002

出　　处：《环境污染与防治》2024年第2期181-186,207,共7页Environmental Pollution & Control

基　　金：安徽省自然科学基金资助项目(No.KJ2019A0079、No.KJ2020A0236)。

摘　　要：以钒磷氧化物(VPO)为活性组分,TiO_(2)为载体,通过改变制备条件,制备具有不同表面酸性位特性的钒磷氧催化剂VPO/TiO_(2),并对其低温脱硝活性和表面酸性进行了研究。结果表明,当HCl/V摩尔比为3、V/P摩尔比为5、VPO煅烧温度为450℃时,制得的VPO/TiO_(2)催化剂表现出优异的脱硝活性,200℃时脱硝效率接近100%。VPO/TiO_(2)催化剂主要活性晶相为(VO)2P_(2)O_(7)、V_(2)O_(5)和VOPO_(4)。催化剂表面具有大量的酸性位点,通过数据拟合建立了脱硝活性与表面酸量间的相关性,结果表明所有VPO/TiO_(2)催化剂的低温脱硝活性均与弱Lewis酸含量呈正相关(相关系数>0.9)。此外,对脱硝机理进行研究表明,NH3以配位态NH_(3)或NH_(4)^(+)吸附于VPO/TiO_(2)表面,并参与后续选择性催化还原(SCR)反应,反应过程中NO被氧化成NO_(2)或单齿硝酸盐后最终被还原。在VPO/TiO_(2)催化剂的SCR反应过程中Eley-Rideal机理和Langmuir-Hinshelwood机理并存。Vanadium phosphorus oxygen catalysts VPO/TiO_(2) with different surface acidity characteristics were prepared using vanadium phosphorus oxygen(VPO)as active component and TiO_(2) as support by changing the preparation conditions.Their low temperature denitrification activities and surface acidity were studied.The results showed that when HCl/V molar ratio was 3,V/P molar ratio was 5 and the calcination temperature of VPO was 450℃,the obtained VPO/TiO_(2) catalyst exhibited excellent denitration activity,with nearly 100%denitration rate at 200℃.The main active crystal phases of VPO/TiO_(2) catalysts were(VO)2 P_(2)O_(7),V_(2)O_(5)and VOPO_(4).VPO/TiO_(2) surface had a large number of acidic sites,and the correlation between the denitrification activity and the amount of acid on the catalyst surface was established by data fitting,which showed that the low-temperature denitrification activities of all VPO/TiO_(2) catalysts were positively correlated with the weak Lewis acid content(correlation coefficient>0.9).In addition,the denitrification mechanism studies revealed that the NH 3 adsorbed on VPO/TiO_(2) surface in state of coordination NH_(3) or NH_(4)^(+),and participate in the further selective catalytic reduction reaction.The NO was oxidized to NO_(2),monodentate nitrate before eventually reduced.SCR reaction over VPO/TiO_(2) followed the Eley-Rideal and Langmuir-Hinshelwood mechanism simutanously.

关 键 词：低温脱硝 SCR VPO/TiO_(2) 表面酸性位 脱硝机理 

分 类 号：X701[环境科学与工程—环境工程]