Preparation and characterization of (CeO2)x-(Fe2O3)1-x nanocomposites:reduction kinetics and hydrogen storage

作     者：Shimaa G.Sayed Waleed M.A.El Rouby Ahmed A.Farghali Shimaa G.Sayed;Waleed M.A.El Rouby;Ahmed A.Farghali

作者机构：Materials Science and Nanotechnology DepartmentFaculty of Postgraduate Studies for Advanced Science(PSAS)Beni-Suef UniversityBeni Suef62511Egypt 

出 版 物：《Rare Metals》 (稀有金属（英文版）)

年 卷 期：2020年第39卷第3期

页      面：218-229页

核心收录：

学科分类：08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

基　　金：Beni-Suef University for supporting this work 

主　　题：CeO2-Fe2O3 nanocomposite Reduction kinetics Reduction mechanism Hydrogen storage Oxygen vacancies 

摘      要：A series of nanosized CeO2-Fe2O3 mixed-oxide nanocomposites with different Ce4+/Fe3+molar ratios were successfully prepared by a co-precipitation *** surface area increased with Fe2O3 content increasing up to 60 wt%in the ***,with further increase in Fe2O3 content,the surface area began to *** reduction processes of the CeO2-Fe2O3 nanocomposites were studied in a hydrogen atmosphere at 300-600℃.The reduction rates increased by increasing both the temperature and Fe2O3 content in the *** microstructure of the reduced composites at 500℃illustrated the presence of a considerable number of macro-and *** activation energy values were calculated which were in the range of 3.56-5.37 kJ mol-1 at the initial stages(up to 35%reduction)and 5.21-10.2 kJ·mol-1 at the final stages(up to 80%reduction)of *** rate-controlling mechanisms in both the initial and final reduction stages were determined,and the initial reaction stage was controlled by combined gaseous diffusion and interfacial chemical reaction mechanisms for all the composites except for pure CeO2,which was controlled by a chemical reaction *** final reaction stage was controlled by a gaseous diffusion mechanism for some composites,while for the others it was controlled by combined gaseous diffusion and interfacial chemical reaction *** hydrogen sorption properties of the nanocomposites were studied by pressure composition isotherms using a volumetric *** storage in the nanocomposites increased by increasing the temperature because of the formation of oxygen vacancies which enhance atomic H adsorption and function as strong adsorption sites forming more metal hydride covalent bonds.