Ling Weitong, Zhao Haijun, Wu Shilin, Tang Zhicheng, Zha Fei
State Key Laboratory for Oxo Synthesis and Selective Oxidation, and, National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, P. R. China.
College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, 730000, P. R. China.
Chemistry. 2021 Jul 16;27(40):10356-10368. doi: 10.1002/chem.202100392. Epub 2021 Jun 14.
A series of catalysts with different core-shell structures has been successfully prepared by a hydrothermal method. They consisted of CeCoO @TiO (single shell), CeCoO @Nb O (single shell) and CeCoO @Nb O @TiO (double shell) core-shell nanocages and CeCoO nanocages, in which CeCoO was the core and TiO and Nb O were shells. The influence of the core-shell structure on the catalytic performance of o-dichlorobenzene was investigated by activity, water-resistance, and thermal stability tests as well as catalyst characterization. The temperatures corresponding to 90 % conversion of o-dichlorobenzene (T ) of CeCoO , CeCoO @TiO , CeCoO @Nb O , and CeCoO @Nb O @TiO catalysts were 415, 383, 362 and 367 °C, respectively. CeCoO @Nb O exhibited excellent catalytic activity, mainly owing to the special core-shell structure, large specific surface area, abundant activity of Co , Ce , Nb , strong reducibility, and more active oxygen vacancies. It can be seen that the Nb O coating can greatly improve the catalytic activity of the catalyst. In addition, due to the protective effect of the TiO shell on CeCoO , CeCoO @Nb O @TiO catalysts exhibited outstanding thermal and hydrothermal stability for 20 hours. The T of CeCoO @Nb O @TiO was slightly lower than that of CeCoO @Nb O , but it had higher stability and hydrothermal stability. Furthermore, possible reaction pathways involving the Mars-van-Krevelen (MvK) and Langmuir-Hinshelwood (L-H) models were deduced based on studies of the temperature-programmed desorption of O (O -TPD), X-ray photoelectron spectroscopy (XPS), and in situ diffuse reflectance FTIR spectroscopy (DRIFTS) characterization.
通过水热法成功制备了一系列具有不同核壳结构的催化剂。它们由CeCoO@TiO（单壳）、CeCoO@Nb₂O₅（单壳）和CeCoO@Nb₂O₅@TiO（双壳）核壳纳米笼以及CeCoO纳米笼组成，其中CeCoO为核，TiO和Nb₂O₅为壳。通过活性、耐水性、热稳定性测试以及催化剂表征研究了核壳结构对邻二氯苯催化性能的影响。CeCoO、CeCoO@TiO、CeCoO@Nb₂O₅和CeCoO@Nb₂O₅@TiO催化剂的邻二氯苯90%转化率对应的温度（T₉₀）分别为415、383、362和367℃。CeCoO@Nb₂O₅表现出优异的催化活性，主要归因于其特殊的核壳结构、大比表面积、丰富的Co、Ce、Nb活性、强还原性以及更多的活性氧空位。可以看出，Nb₂O₅涂层可大大提高催化剂的催化活性。此外，由于TiO壳对CeCoO的保护作用，CeCoO@Nb₂O₅@TiO催化剂在20小时内表现出出色的热稳定性和水热稳定性。CeCoO@Nb₂O₅@TiO的T₉₀略低于CeCoO@Nb₂O₅，但具有更高的稳定性和水热稳定性。此外，基于程序升温脱附O₂（O₂-TPD）、X射线光电子能谱（XPS）和原位漫反射傅里叶变换红外光谱（DRIFTS）表征研究，推导了可能涉及Mars-van-Krevelen（MvK）和Langmuir-Hinshelwood（L-H）模型的反应途径。
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