CeO2基储氧材料的制备和表征  

Preparation and Characterization of CeO2-based Oxygen Storage Materials

作　　者：李红梅[1,2] 兰丽 刘达玉[1] 王卫[1] 薛慧玲[1] 漆文胜[1] 龚茂初[2] 陈耀强[2] Li Hongmei;Lan Li;Liu Dayu;Wang Wei;Xue Hu iling;Qi Wen sheng;Gong Maochu;Chen Yaoqiang(Chengdu University,Chengdu 610106,China;Key Laboratory of Green Chemistry&Technology,Ministry of Education,Sichuan University,Chengdu 610064,China)

机构地区：[1]成都大学,四川成都610106 [2]四川大学绿色化学与技术教育部重点实验室,四川成都610064

出　　处：《稀有金属材料与工程》2020年第3期769-777,共9页Rare Metal Materials and Engineering

基　　金：National Hi-tech Research and Development Program of China(“863”,Program,2015AA034603);Opening Project of Key Laboratory of Sichuan Institutes of Higher Education(15-S07,16-R04)。

摘　　要：用共沉淀法制备了4种CeO2基储氧材料,并用X射线衍射(XRD),Raman光谱,N2吸附-脱附(BET方法),H2程序升温还原(H2-TPR),氧脉冲技术,X射线光电子能谱(XPS)和扫描电子显微镜(SEM)表征了其物理化学性质。XRD结果表明,在CeO2和CeO2-Al2O3(CA)中只能检测到宽的CeO2的特征峰,而CeO2-ZrO2(CZ)和CeO2-ZrO2-Al2O3(CZA)中检测到了Ce0.75Zr0.25O2相,所有的CeO2基储氧材料中都形成了均匀的固溶体。XPS结果表明,三价铈和四价铈共存于CZ,CA和CZA的表面,而在纯CeO2中几乎检测不到三价铈的存在。CZA表现出了最佳的织构性能,高的储氧量(OSC)和优异的热稳定性。另外,为了阐释4个样品的差异,提出了一种新的观点:Al3+可能插入了萤石结构的间隙或者高度分散在固溶体中。CZA固溶体可能是由间隙型固溶体和置换型固溶体混合组成的,这一点由CA和CZA中存在2种不同的氧化物或者2种类型的氧通道可以证明。然而,关于这个观点的详细证据还不够充分,需要继续进行深入的研究。Four types of CeO2-based oxide storage materials were prepared by co-precipitation, and their physicochemical properties were characterized by X-ray diffraction(XRD), Raman spectroscopy, N2 adsorption-desorption(BET), H2-temperature-programmed reduction(H2-TPR), oxygen pulsing technique, X-ray photoelectron spectroscopy(XPS) and scanning electron microscopy(SEM). XRD patterns reveal that only characteristic peaks of CeO2 are observed in the CeO2 and CeO2-Al2O3(CA), while CeO2-ZrO2(CZ) and CeO2-ZrO2-Al2O3(CZA) show Ce0.75Zr0.25O2 phases. XPS studies show that 4+ and 3+ oxidation states of cerium coexist on the surface of CZ, CA and CZA. However, almost no 3+ oxidation state is detected in pure CeO2. The best textural properties, higher oxygen storage capacity(OSC) and excellent thermal stability are obtained for CZA. In addition, in order to compare the differences among the four samples, a new insight is proposed that Al3+ might be inserted into the inter-space of the fluorite structure or highly dispersed in the solid solution. CZA solid solution may consist of interstitial solid solution and substitutional solid solution, which can be verified by the presence of two oxide species or two types of oxygen channels in CA and CZA. However, the evidence is not detailed enough to support this argument, so further investigation is necessary.

关 键 词：CeO2基储氧材料 热稳定性 共沉淀 储氧量(OSC) Ce原子利用率 

分 类 号：TB34[一般工业技术—材料科学与工程]