Mesostructured Cu-Mn-Ce-O composites with homogeneous bulk composition for chlorobenzene removal: Catalytic performance and microactivation course
Mesostructured Cu-Mn-Ce-O composites with homogeneous bulk composition for chlorobenzene removal: Catalytic performance and microactivation course
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用于去除氯苯的具有均匀整体成分的介观结构 Cu-Mn-Ce-O 复合材料：催化性能和微活化过程
DOI：
10.1016/j.matchemphys.2015.03.020
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发表时间：
2015-05-01
影响因子：
4.6
通讯作者：
Liu, Hongxia
中科院分区：
文献类型：
--
作者：
He, Chi;Yu, Yanke;Liu, Hongxia
采用均相共沉淀法(HCP)合成了比表面积增大、介孔发达的Cu-Mn-Ce-O复合材料，并对其催化裂解氯苯进行了研究。采用X射线衍射仪、氮气吸附/脱附、场发射扫描电子显微镜、透射电子显微镜、X射线光电子能谱、程序升温还原、CB/O-2程序升温脱附、漫反射紫外可见光谱等手段对催化剂的结构和织构性能进行了表征。锰和铜以类萤石结构进入CeO2基质，并产生大量氧空位。锰的加入促进了还原铜相的形成，大量高价Mn4+离子的存在大大增强了复合材料中Cu2+-Cu2+的氧化还原电偶。合成工艺和金属掺杂量对催化剂的还原性能、表面态和氧密度均有显著影响。HCP法合成的Cu0.15Mn0.15Ce0.85Ox具有最高的催化活性，在255℃时，90%的氯苯被破坏(CO2选择性99.5%)。丰富的表面氧、良好的活性氧迁移率和CB的吸附能力保证了Cu-Mn-Ce-O复合催化剂优异的活性和稳定性。在氯苯的破坏过程中，亲核取代和亲电取代依次发生，吸附的氯最终可以通过Deacon反应以氯-2的形式被去除。此外，CuO和MnOx相的加入可以抑制有机副产物的形成，如酚酸盐、马来酸盐和邻苯二酚类物种，特别是在较高的反应温度下。(C)2015爱思唯尔B.V.保留所有权利。
Cu-Mn-Ce-O composites with enhanced surface area and developed mesoporosity were synthesized using a homogeneous coprecipitation (hcp) method, and were tested in the catalytic destruction of chlorobenzene (CB). X-ray diffraction (XRD), N-2 adsorption/desorption, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction (H-2-TPR), temperature programmed desorption of CB/O-2 (CB/O-2-TPD), and diffuse reflectance ultraviolet visible spectroscopy (DRUV-Vis) were used to characterize the structure and textural properties of catalysts. Mn and Cu enter CeO2 matrix with a fluorite-like structure, and produce large amounts of oxygen vacancies. Addition of manganese promotes the formation of reduced copper phase, and the presence of large numbers of high valence Mn4+ ions strongly enhances the redox couple of Cu+-Cu2+ in the composites. Both the synthesis protocol and metal doping amount significantly affect the catalyst reducibility, surface state and oxygen density. Cu0.15Mn0.15Ce0.85Ox synthesized via the hcp method exhibits the highest catalytic activity with 90% of chlorobenzene destructed at 255 degrees C (CO2 selectivity > 99.5%). Enriched surface oxygen, excellent active oxygen mobility and CB adsorption ability guarantee the superior activity and stability of Cu-Mn-Ce-O composite catalysts. Nucleophilic and electrophilic substitutions happen in sequence during chlorobenzene destruction, and the adsorbed Cl can be finally removed in the form of Cl-2 via the Deacon reaction. Furthermore, the incorporation of CuO and MnOx phases can inhibit the formation of organic byproducts, such as phenolates, maleates, and o-benzoquinone-type species, especially at elevated reaction temperatures. (C) 2015 Elsevier B.V. All rights reserved.