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Confined Transformation of Organometal‐Encapsulated MOFs into Spinel CoFe2O4/C Nanocubes for Low‐Temperature Catalytic Oxidation
Advanced Functional Materials ( IF 18.5 ) Pub Date : 2020-02-19 , DOI: 10.1002/adfm.201910257
Lei Qin 1 , Zehai Xu 1 , Yilian Zheng 1 , Chang Li 1 , Jingwen Mao 1 , Guoliang Zhang 1
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Development of spinel bimetallic oxides as low‐cost and high‐efficiency catalysts for catalytic oxidation is highly desired. However, rational design of spinel oxides with controlled structure and components still remains a challenge. A general route for large‐scale preparation of spinel CoFe2O4/C nanocubes transformed from organometal‐encapsulated metal–organic frameworks (MOFs) via exchange–coordination and pyrolysis combined method is reported. Strong confinement effect between organometallics and MOFs realizes reconstruction of crystal phase and composition, but not simple metallic oxides support by Co2+ introduction. Compared with Co3O4‐Fe2O3/C, MOFs‐derived cubic nano‐CoFe2O4/C with higher surface area (115.7 m2 g−1) and favorable surface chemistry exhibits excellent catalytic activity (100% CO conversion at 105 °C) and competitive water‐resisting stability (total conversion at 145 °C for 20 h). Turnover frequency of CoFe2O4/C reaches 4.26 × 10−4 s−1 at 90 °C, two orders of magnitude higher than commercial Co3O4 . Theoretical models show that oxygen vacancies (17.7%) at exposed {112} facet on the carbon interface take superiority in nanocubic spinel phase, which allows reactive species to be strongly adsorbed on nanostructured catalysts' surface and plays key roles in hindering deactivation under moisture rich conditions. The progresses offer a promising way in the development of novel spinel oxides with tailored architecture and properties for vast applications.

中文翻译:

有机金属封装的MOF的有限转变为尖晶石CoFe2O4 / C纳米立方体,用于低温催化氧化

迫切需要开发尖晶石双金属氧化物作为低成本和高效的催化氧化催化剂。但是,合理设计具有受控结构和组分的尖晶石氧化物仍然是一个挑战。报道了通过交换-配位和热解联合方法从有机金属封装的金属-有机骨架(MOF)转化大规模制备尖晶石CoFe 2 O 4 / C纳米立方体的一般方法。有机金属和MOF之间的强限制作用实现了晶体相和组成的重构,但是通过引入Co 2+不能简单地支持金属氧化物。与Co 3 O 4 ‐Fe 2 O 3相比/ C,MOF衍生的立方纳米CoFe 2 O 4 / C,具有较高的表面积(115.7 m 2 g -1)和良好的表面化学性质,具有出色的催化活性(105°C下100%的CO转化率)和具有竞争力的耐水性能稳定性(在145°C下进行20小时的总转化)。CoFe 2 O 4 / C的周转频率在90° C时达到4.26×10 -4 s -1,比商用Co 3 O 4高两个数量级。。理论模型表明,碳界面上{112}面暴露的氧空位(17.7%)在纳米立方尖晶石相中具有优势,这使反应性物种被强烈吸附在纳米结构催化剂的表面上,并在阻止富湿条件下失活中起关键作用条件。这些进展为开发具有定制结构和性能的新型尖晶石氧化物提供了一种有前途的方法,可用于广泛的应用。
更新日期:2020-04-06
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