摘要
采用共沉淀法制备了不同摩尔比(x=0,0.1,0.2～0.9,1.0)的CexTi1-xO2复合氧化物,考察了CuO/CexTi1-xO2对NO+CO反应的活性,并用BET,TPR和XRD等技术对各试样进行了表征。结果表明,试样的结构和还原特性随焙烧温度变化而变化。XRD检测表明,x值从0.1增加到0.5时,650℃焙烧的试样已形成了CeTi2O6物相,且主要以无定形状态存在;试样经800℃焙烧后晶化完全;x>0.6时,一些TiO2已经进入了CeO2晶格,形成了Ce Ti固溶体。催化剂活性评价表明CuO/CexTi1-xO2(650℃)对NO+CO反应具有较好的活性,其活性随x值变化而变化。TPR及XRD结果表明CuO与CeTi2O6之间存在很强的相互作用,CeTi2O6物相的形成使CuO的还原峰温由380℃提前到200℃,而CuO的存在又促进CeTi2O6的还原峰温从600℃提前至200～300℃。
CexTi1-xO2 mixed oxides at different mole ratios (x=0, 0.1 , 0.2～0.9, 1.0) were prepared by co-precipitation. The effects of CuO/Cex Ti1-xO2 on NO+CO reaction were investigated, and the structure and reductive properties of CexTi1-xO2 and CuO/CexTi1- xO2 were characterized by the methodologies of BET, TPR and XRD. The re sults show that different Ce/Ti mole ratios and the calcination temperatures i nduce changes of structure and reductive properties of the CexTi1-x O2 mixed oxides. When x=0.1～05, amorphous CeTi2O6 phase is mai n ly formed at calcination temperature of 650 ℃, and crystallation processing fin ishes at 800 ℃. When x>0.6, some TiO2 enter CeO2 lattice, and a CeO 2-TiO2 solid solution formes. 6%CuO/CexTi1-xO2 (650 ℃) has high activity on NO+CO reaction, which is largely affected by the x value. There are strong interactions between CuO and CeTi2O6, i.e., formation of t he CeTi2O6 phase shiftes CuO reduction peak temperature from 380 to 200 ℃, and CuO, in turn, shiftes CeTi2O6 reduction peak temperature from 600 to 300 ℃.
出处
《中国稀土学报》
CAS
CSCD
北大核心
2003年第4期435-440,共6页
Journal of the Chinese Society of Rare Earths
基金
浙江省杭州市科委资助项目(2001124B38)
杭州市环保局资助项目(200220)
