摘要
通过调变分步浸渍法制备过程中的溶液pH值,制备了一系列的铈钨钛复合金属氧化物催化剂,以研究它们在NH3-SCR(NH3-Selective catalytic reduction)反应中的脱硝表现。重点考察了催化剂制备过程中溶液的pH值的变化对脱硝催化剂的影响。XRD表征结果显示,提高pH值有利于氧化钨在催化剂表面的高分散。XPS分析、NH3-TPD分析及NH3-SCR活性测试的结果显示,随着制备过程中pH值的增大,催化剂的表面W原子浓度、Ce^3+/Ce^4+比、Oα/Oβ比、表面酸量或NOx转化率都呈现先上升然后趋缓(或略降低)的变化趋势。高分散的WO3物种与CeO2物种之间的相互作用及表面W原子浓度一定程度的升高被认为是催化剂脱硝活性上升的主要原因。在pH=9的条件下制得的铈钨钛复合金属氧化物催化剂展现了最优的SCR脱硝活性,并在300℃~450℃范围内NOx转化率保持在90%以上。
A series of CeWTi mixed metal oxide catalysts were prepared by varying the solution pH during the stepwise impregnation process,to investigate their denitration performance in NH3-SCR(NH3-selective catalytic reduction)reaction.This study focused on the effect of the solution pH during catalyst preparation on the denitration catalysts.XRD results showed that increasing the pH value could enhance the high dispersion of WO3 on the catalyst surface.The results of XPS analysis,NH3-TPD analysis,and NH3-SCR activity test showed that,as the pH value increased during the catalyst preparation process,the surface W concentration,Ce^3+/Ce^4+ ratio,Oα/Oβratio,surface acid content,or NOx conversion showed a trend of rising first and then slowing(or slightly decreasing).The interaction between highly-dispersed WO3 species and CeO2 species and the increased surface concentration of W atom(to some extent)were considered to be the main reasons for the improved denitration activity.The CeWTi mixed metal oxide catalyst prepared at pH=9 showed the best SCR denitration activity,and the NOx conversion remained above 90%in the range of 300℃~450℃.
作者
周超
赵阳
徐佳
孟浩
浦渊竞
戚国琴
赵洁
郭燏
ZHOU Chao;ZHAO Yang;XU Jia;MENG Hao;PU Yuan-jing;QI Guo-qin;ZHAO Jie;GUO Yu(State Key Laboratory of Materials-oriented Chemical Engineering,College of Chemical Engineering,Nanjing Tech University,Nanjing 211816,China;School of Environmental Sciences and Engineering,Nanjing Tech University,Nanjing 211816,China)
出处
《稀土》
EI
CAS
CSCD
北大核心
2020年第5期59-69,共11页
Chinese Rare Earths
基金
院企合作横向课题(18090502)。
