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Large Dimensional CeO2 Nanoflakes by Microwave‐Assisted Synthesis: Lamellar Nano‐Channels and Surface Oxygen Vacancies Promote Catalytic Activity
ChemCatChem ( IF 4.5 ) Pub Date : 2018-07-24 , DOI: 10.1002/cctc.201800784
Huihui Ding 1 , Jingxia Yang 1, 2 , Shuyi Ma 1 , Nevzat Yigit 2 , Jingli Xu 1 , Günther Rupprechter 2 , JinJie Wang 1
Affiliation  

Large nano‐structured flakes of CeO2 (20–80 nm in thickness, up to 5.6 μm in diameter) were synthesized by a combination of microwave (MW), ultraviolet (UV) and ultrasound (US), with or without pressure (P). The CeO2 structures were systematically examined by XRD, SEM, N2 sorption, HRTEM, XPS, Raman and H2‐TPR. The synthesized CeO2 nanoflakes were composed by 3.0–7.5 nm nanoparticles with the (111) surface exposed, and laminated to nanoflakes with 3.42–3.85 nm nano‐channels in between. MW‐assisting was beneficial to form a higher surface Ce3+/(Ce3++Ce4+) ratio and surface oxygen vacancies during short synthesis procedure. A Raman peak at 480 cm−1 correlating with bulk Ce3+ was detected. H2‐TPR found MW and MW+P had more surface Ce3+ (surface oxygen vacancies). CO oxidation and imine conversion proved that MW+P was the optimum condition to produce highly active CeO2 nanoflakes. The much better catalytic performance than CeO2 from solvothermal preparation, due to the larger channel gap (3.85 nm),a higher Ce3+/(Ce3++Ce4+) ratio (32 %) and more surface oxygen vacancies on the particles of the organized flake structures.

中文翻译:

微波辅助合成的大尺寸CeO2纳米薄片:层状纳米通道和表面氧空位促进催化活性

通过微波(MW),紫外线(UV)和超声(US)的组合,在有或没有压力的情况下,合成了大型的纳米结构的CeO 2薄片(厚度为20-80 nm,直径最大为5.6μm)(P )。通过XRD,SEM,N 2吸附,HRTEM,XPS,拉曼和H 2 -TPR系统检查了CeO 2的结构。合成的CeO 2纳米薄片由3.0-7.5 nm的纳米颗粒组成,该纳米颗粒的(111)表面暴露在外,然后层压到其间具有3.42-3.85 nm纳米通道的纳米薄片上。MW辅助有利于形成更高的表面Ce 3+ /(Ce 3+ + Ce 4+合成过程中的比值和表面氧空位)。在480cm -1处检测到与大量Ce 3+相关的拉曼峰。H 2 -TPR发现MW和MW + P具有更多的表面Ce 3+(表面氧空位)。CO氧化和亚胺转化证明MW + P是生产高活性CeO 2纳米薄片的最佳条件。与溶剂热法制备的CeO 2相比,其催化性能要好得多,这是由于较大的通道间隙(3.85 nm),较高的Ce 3+ /(Ce 3+ + Ce 4+)比(32%)和更多的表面氧空位。片状结构的颗粒。
更新日期:2018-07-24
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