Ren Xiaoning, Zhang Zhixin, Wang Yehong, Lu Jianmin, An Jinghua, Zhang Jian, Wang Min, Wang Xinkui, Luo Yi
State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology Dalian 116024 Liaoning China.
State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences Dalian 116023 Liaoning China
RSC Adv. 2019 May 15;9(27):15229-15237. doi: 10.1039/c9ra02353d. eCollection 2019 May 14.
Understanding of surface active sites (SAS) of CeO is crucial to its catalytic applications. In the present study, we have employed capping experiments, DFT calculations, and spectroscopic characterization to study pristine CeO catalyst. We find that multiple SAS coexist on the CeO surface: oxygen vacancies as redox sites and the coordinately unsaturated Ce cations near the oxygen vacancies and the neighboring oxygen ions as Lewis acid-base sites. Dimethylsulfoxide (DMSO), pyridine, and benzoic acid are utilized to cap the redox sites, Lewis acid sites, and base sites, respectively. Selective capping on the redox site does not have much effect on the acid-base catalysis, and , indicating the distinct surface proximity and independent catalysis of these SAS. We draw attention to a relationship between the well-known redox sites and the surface Lewis acid and Lewis base pairs on CeO surface, which are responsible for driving various heterogeneous catalytic reactions.
了解CeO的表面活性位点（SAS）对其催化应用至关重要。在本研究中，我们采用了封端实验、密度泛函理论（DFT）计算和光谱表征来研究原始CeO催化剂。我们发现CeO表面共存多个SAS：作为氧化还原位点的氧空位、氧空位附近配位不饱和的Ce阳离子以及作为路易斯酸碱位点的相邻氧离子。分别使用二甲基亚砜（DMSO）、吡啶和苯甲酸来封端氧化还原位点、路易斯酸位点和碱位点。对氧化还原位点的选择性封端对酸碱催化影响不大，这表明这些SAS具有明显的表面邻近性和独立催化作用。我们关注到CeO表面上著名的氧化还原位点与表面路易斯酸和路易斯碱对之间的关系，它们负责驱动各种多相催化反应。
