摘要
制备了氧化铝、铈锆复合氧化物负载铂、钯的双金属催化剂Pt-Pd/Ce_(0.3)Zr_(0.7)O_(2)-Al_(2)O_(3),用于柴油车尾气中CO、HC和NO的催化氧化.通过添加3% ZrO_(2)助剂改性,并考察制备过程中焙烧温度对性能的影响,进一步优化催化剂性能.活性评价结果表明,添加ZrO_(2)明显提高了催化剂的低温氧化活性.焙烧温度对催化剂的氧化性能有较大影响,焙烧温度为800℃时,催化剂Pt-Pd-(3%) ZrO_(2)/Ce_(0.3)Zr_(0.7)O_(2)-Al_(2)O_(3)对CO和C_(3)H_(6)转化的起燃温度最低,分别为168、189 ℃;焙烧温度为700 ℃时,NO转化为NO;的转化率最高,最大转化率为36%,催化剂表现出较好的热稳定性.通过XRD、N_(2)吸附-脱附、CO化学吸附、XPS、H_(2)-TPR等表征手段研究了催化剂物理化学性质随焙烧温度的变化,分析了其与催化活性之间的关系,得到不同焙烧温度制备的催化剂的物理化学性质不同,而贵金属分散度、表面活性氧含量、还原能力等性质协同影响氧化活性.通过优化焙烧温度提升柴油车氧化催化剂性能,对提高工业应用柴油车尾气后处理系统的净化效率有重要意义.
Bimetallic Pt-Pd catalysts supported on Al_(2)O_(3)and Ce_(0.3)Zr_(0.7)O_(2)with total Pt&Pd loading of only 0.68%(Mass fraction) were prepared and used as diesel oxidation catalysts.3%ZrO_(2)was then added into the system as a promoter to enhance activities.Meanwhile,effects of calcination temperature on performance were investigated.Catalytic performance towards CO,C_(3)H_(6)and NO oxidation over Pt-Pd-(3%) ZrO_(2)/Ce_(0.3)Zr_(0.7)O_(2)-Al_(2)O_(3)catalysts calcined at different temperatures were compared with catalyst without ZrO_(2)added.Catalytic activities evaluation results indicated that ZrO_(2)doping significantly enhanced the low-temperature oxidation activities.Furthermore,calcination temperature has great effectson the catalytic performance.The lowest light-off temperature of CO and C_(3)H_(6)were obtained over ZrO_(2)modified catalyst calcined at 800℃and were 168 and 189℃,respectively.The optimal conversion of NO to NO_(2)was acquired when the calcination temperatureis 700℃with the maximum conversion of 36%.The catalysts exhibited good thermal stability.XRD,N_(2)adsorption-desorption,CO chemisorption,XPS and H_(2)-TPR were used to characterize the physical and chemical properties of catalysts calcined at different temperatures.It was found that noble metal dispersion,surface-chemisorbed oxygen species,and reducibility of catalysts,which were affected by calcination temperature,influenced the catalytic performance synergistically.Therefore,the catalytic oxidation activities could be improved by adjusting calcination temperature.The results are significant for improving purification efficiency of diesel catalytic system.
作者
樊蓉蓉
李兆强
王雨
丁智勇
王艳
张丞
康娜
郭欣
王荣
FAN Rong-rong;LI Zhao-qiang;WANG Yu;DING Zhi-yong;WANG Yan;ZHANG Cheng;KANG Na;GUO Xin;WANG Rong(State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization,Baotou Research Institute of Rare Earths,Baotou 014030,China;National Engineering Research of Rare Earth Metallurgy and Functional Materials,Baotou 014030,China)
出处
《分子催化》
CAS
CSCD
北大核心
2021年第5期428-439,I0002,共13页
Journal of Molecular Catalysis(China)
基金
北方稀土科技计划(BFXT-2019-D-028)。
关键词
柴油车氧化催化剂
铂
钯
氧化锆
焙烧温度
催化作用
diesel oxidation catalyst
Platinum
Palladium
zirconium oxide
calcination temperature
catalysis
