title: Morphology-dependent interplay of reduction behaviors, oxygen vacancies and hydroxyl reactivity of CeO2 nanocrystals.
abstract: Reduction behaviors, oxygen vacancies and hydroxyl groups play decisive roles in the surface chemistry and catalysis of oxides. Employing isothermal H2 reduction we simultaneously reduced CeO2 nanocrystals with different morphologies, created oxygen vacancies and produced hydroxyl groups. The morphology of CeO2 nanocrystals was observed to strongly affect the reduction process and the resultant oxygen vacancy structure. The resultant oxygen vacancies are mainly located on the surfaces of CeO2 cubes and rods but in the subsurface/bulk of CeO2 octahedra. The reactivity of isolated bridging hydroxyl groups on CeO2 nanocrystals was found to depend on the local oxygen vacancy concentration, in which they reacted to produce water at low local oxygen vacancy concentrations but to produce both water and hydrogen with increasing local oxygen vacancy concentration. These results reveal a morphology-dependent interplay among the reduction behaviors, oxygen vacancies and hydroxyl reactivity of CeO2 nanocrystals, which deepens the fundamental understanding of the surface chemistry and catalysis of CeO2.
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Materials for Energy Conversion and Department of Chemical Physics, University of Science and Technology of China, Jinzhai Road 96, Hefei 230026, P. R. China. huangwx@ustc.edu.cn.
authors.forename: Yuxian
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Materials for Energy Conversion and Department of Chemical Physics, University of Science and Technology of China, Jinzhai Road 96, Hefei 230026, P. R. China. huangwx@ustc.edu.cn.
authors.forename: Rongtan
authors.initials: R
authors.lastname: Li
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Materials for Energy Conversion and Department of Chemical Physics, University of Science and Technology of China, Jinzhai Road 96, Hefei 230026, P. R. China. huangwx@ustc.edu.cn.
authors.forename: Shilong
authors.initials: S
authors.lastname: Chen
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Materials for Energy Conversion and Department of Chemical Physics, University of Science and Technology of China, Jinzhai Road 96, Hefei 230026, P. R. China. huangwx@ustc.edu.cn.
authors.forename: Liangfeng
authors.initials: L
authors.lastname: Luo
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Materials for Energy Conversion and Department of Chemical Physics, University of Science and Technology of China, Jinzhai Road 96, Hefei 230026, P. R. China. huangwx@ustc.edu.cn.
authors.forename: Tian
authors.initials: T
authors.lastname: Cao
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Materials for Energy Conversion and Department of Chemical Physics, University of Science and Technology of China, Jinzhai Road 96, Hefei 230026, P. R. China. huangwx@ustc.edu.cn.
authors.forename: Weixin
authors.initials: W
authors.lastname: Huang