Pr掺杂Ni~(Ce-Zr)O_(2)/Al_(2)O_(3)用于三效催化(TWC)反应:缺陷性质-活性关系  

Pr-doped Ni~(Ce-Zr)O_(2)/Al_(2)O_(3)for TWC reaction:Defect property-activity relationship

作　　者：张彤 李巧艳 王小燕 梁美生[1] 莱卓君 ZHANG Tong;LI Qiao-yan;WANG Xiao-yan;LIANG Mei-sheng;LAI Zhuo-jun(College of Environmental Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学环境科学与工程学院,山西太原030024

出　　处：《中国环境科学》2023年第10期5257-5269,共13页China Environmental Science

基　　金：山西省基础研究计划项目(202203021211140,20210302124131)。

摘　　要：为探究稀土金属掺杂CeZrO_(x)催化剂引发的缺陷结构对汽车尾气污染控制的影响,合成了不同Pr掺杂量的Ni~(Ce_(6)Zr_(4-x)Pr_(x))O_(2)/Al_(2)O_(3)系列催化剂,并对其进行了TWC催化活性评价、耐SO_(2)性能测试和系统性表征,研究Pr掺杂引起的缺陷性质对催化性能的影响.结果表明,Pr掺杂Ni~(Ce-Zr)O_(2)/Al_(2)O_(3)产生两种缺陷:氧空位(O_(v))和晶格扭曲,Pr的掺杂水平控制着缺陷位的类型和浓度.O_(v)在TWC反应中起关键作用.在Pr掺杂的Ni~(Ce_(6)Zr_(4-x)Pr_(x))O_(2)/Al_(2)O_(3)催化剂中,TWC的催化性能显著地依赖于O_(v)浓度,Pr掺杂产生的O_(v)可改善NiO的分散,加速本体氧的迁移和扩散,促进大量活性氧物种的形成,促进CO和HC的吸附和氧化,也可激活和削弱N-O键促进NO的解离.具有最多O_(v)数量的Ni~(Ce6Zr3Pr1)O_(2)/Al_(2)O_(3)在200~600℃时表现出最突出的三效催化性能和较好的抗硫性能,而晶格扭曲对催化性能影响并不大.To investigate the influence of defect structures in CeZrO_(x)catalysts,which induced by rare earth metal doping,on the control of automotive exhaust pollution,series of Ni~(Ce_(6)Zr_(4-x)Pr_(x))O_(2)/Al_(2)O_(3)catalysts with varied Pr doping content were synthesized,and their TWC activities and SO_(2)resistance performance were tested.The prepared catalysts were also systematically characterized.The collected results suggested that two kinds of defects in Ni~(Ce-Zr)O_(2)/Al_(2)O_(3)were generated after Pr doping,including oxygen vacancies(O_(v))and lattice distortion,whose types and concentrations depended on the Pr doping content.The results also indicated that O_(v)play a vital role on the catalytic performance,whereas lattice distortion play a small effect on it.In addition,it is found that the concentrations of O_(v)in as-prepared catalysts determined their TWC catalytic performance,the Ni~(Ce_(6)Zr_(3)Pr_(1))O_(2)/Al_(2)O_(3)catalyst with most O_(v)concentrations performed superior three-way catalytic performance at 200~600℃and also exhibited excellent anti-sulfur poisoning performance after introducing 100ppm SO_(2)at 600℃.This is because O_(v)not only promoted the dispersion of NiO,accelerating the migration and diffusion of bulk oxygen to form active oxygen species,thus promoting the adsorption and oxidation of CO and HC species on the catalyst,but also the O_(v)can weaken the N-O bonds boosting the dissociative adsorption and reduction of NO species.

关 键 词：Ni~(Ce-Zr-Pr)O_(2) Pr掺杂 氧空位(Ov) 晶格扭曲 构效关系 

分 类 号：X703.5[环境科学与工程—环境工程]