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首页> 外文期刊>Chemistry: A European journal >Co/CNF catalysts tailored by controlling the deposition of metal colloids onto CNFs: Preparation and catalytic properties
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Co/CNF catalysts tailored by controlling the deposition of metal colloids onto CNFs: Preparation and catalytic properties

机译：通过控制金属胶体在CNF上的沉积量身定制的Co / CNF催化剂：制备和催化性能

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摘要

Carbon nanofiber-supported Co nanocomposites were prepared by means of a modified ethylene glycol (EG) process, in which the Co salts are reduced in EG and are subsequently deposited onto carbon nanofibers (CNFs). It has been found that the deposition of cobalt colloids onto CNFs can be tailored by simply adjusting the pH of the EG and by heating the mixture of CNFs and colloidal solution at 100 degrees C for some time. The pH value (< 7) and the temperature (at least 100 degrees C) for heating the mixture of CNFs and colloidal solution are found to be the key factors for depositing Co particles onto CNFs. The obtained Co/CNFs have a high and homogeneous dispersion of spherical Co metal particles with a narrow size distribution of 10-15 nm with a peak around 13.5 nm; this result is consistent, to a certain degree, with the value of 12.8 nm obtained from the XRD study. The different states of the stabilizer including carboxylates (pH > 7) and carboxylic acids (pH < 7) as well as the decomposition of carboxylic acids during heat treatment were monitored by using FTIR and UV-visible spectroscopy. On the basis of experimental results, the mechanism of depositing cobalt colloids onto CNFs is also addressed. ne as-synthesized Co/CNF catalysts show excellent activity and regioselectivity for the 1-octene hydroformylation.
机译：碳纳米纤维负载的Co纳米复合材料是通过改性乙二醇（EG）工艺制备的，其中Co盐在EG中还原，然后沉积在碳纳米纤维（CNF）上。已经发现，可以通过简单地调节EG的pH并通过将CNF和胶体溶液的混合物在100℃下加热一段时间来定制钴胶体在CNF上的沉积。发现用于加热CNF和胶体溶液的混合物的pH值（<7）和温度（至少100摄氏度）是将Co颗粒沉积到CNF上的关键因素。所获得的Co / CNF具有高且均匀的球形Co金属颗粒分散体，其粒径分布窄，为10-15 nm，峰值约为13.5 nm。该结果在一定程度上与从XRD研究获得的12.8 nm的值一致。通过使用FTIR和紫外可见光谱法监测稳定剂的不同状态，包括羧酸盐（pH> 7）和羧酸（pH <7）以及热处理过程中羧酸的分解。根据实验结果，还研究了将钴胶体沉积到CNF上的机理。新合成的Co / CNF催化剂对1-辛烯加氢甲酰化反应具有出色的活性和区域选择性。

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