Carbonyl oxygen-coordinated metallic cobalt nanoparticles anchored on hybrid mesoporous silica matrix to enhance 4-nitro
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Carbonyl oxygen-coordinated metallic cobalt nanoparticles anchored on hybrid mesoporous silica matrix to enhance 4-nitrophenol hydrogenation Hang Huo1, Yanqiu Jiang1,*, Zhe Wang1, Yanjing Hu1, Tingting Zhao1, Xing Liu1, Xianzhu Xu1, and Kaifeng Lin1,* 1
MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, P. R. China
Received: 19 May 2020
ABSTRACT
Accepted: 1 September 2020
In this paper, urea group functionalized periodic mesoporous organosilica was utilized as matrix to introduce cobalt precursor into framework. After pyrolysis in nitrogen atmosphere, urea group was decomposed into carbon species and simultaneously the cobalt precursor was reduced to metallic cobalt nanoparticles. The metallic cobalt nanoparticles can be stabilized by coordinating to carbonyl oxygen atoms in carbon species. The supported metallic cobalt exhibited excellent catalytic performance towards 4-nitrophenol hydrogenation reaction. The largest turnover frequency number can reach up to 164.8 h-1, and the reaction rate constant can be as high as 0.77 min-1. The influence of pyrolysis temperature on catalytic performance was also investigated. Compared with the results obtained by samples prepared with wet impregnation method or different pyrolysis rate, it can be concluded that the coordination to carbonyl oxygen atom in carbon species plays a crucial role in improving electron transfer between metallic cobalt and carbon species during catalytic procedure.
Published online: 29 September 2020
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Springer Science+Business
Media, LLC, part of Springer Nature 2020
Handling Editor: Dale Huber.
Address correspondence to E-mail: [email protected]; [email protected]
https://doi.org/10.1007/s10853-020-05263-5
365
J Mater Sci (2021) 56:364–379
GRAPHIC ABSTRACT Metallic cobalt nanoparticles with high dispersion were introduced into urea group functionalized mesoporous silica matrix via pyrolysis in nitrogen atmosphere. The coordination to carbonyl oxygen atom enhances the catalytic performance in 4-nitrophenol hydrogenation.
Introduction Supported cobalt nanoparticles have been greatly applied in many catalytic processes owing to their unique electronic structure [1–3]. Like many other transition metals, metallic cobalt and its oxides are rich in d orbital electrons or empty d orbitals, which allow easy electronic transportation and exchange. This property enables the cobalt nanoparticles prefer to bind with reactants through electronic feedback in d orbitals, which would narrow the activating energy of the reaction. However, limited by their restricted surface area, the exposure of cobalt particles is suppressed, resulting declined catalytic activity and weakened atomic efficiency [4, 5]. In addition, the active cobalt nanoparticles are easy to lose during catalytic process, which is not conducive to recovery and reuse. Thus it is necessary to load the cobalt nanoparticles onto a matr
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