A variety of spherical and structured activated charcoal supported Pt/Fe3O4 composites with an average particle size of ~100 nm have been synthesized by a self-assembly method using the difference of reduction potenti...A variety of spherical and structured activated charcoal supported Pt/Fe3O4 composites with an average particle size of ~100 nm have been synthesized by a self-assembly method using the difference of reduction potential between Pt （Ⅳ） and Fe （Ⅱ） precursors as driving force. The formed Fe3O4 nanoparticles （NPs） effectively prevent the aggregation of Pt nanocrystallites and promote the dispersion of Pt NPs on the surface of catalyst, which will be favorable for the exposure of Pt active sites for high-efficient adsorption and contact of substrate and hydrogen donor. The electron-enrichment state of Pt NPs donated by Fe304 nanocrystallites is corroborated by XPS measurement, which is responsible for promoting and activating the terminal C=O bond of adsorbed substrate via a vertical configuration. The experimental results show that the activated charcoal supported Pt/Fe3O4 catalyst exhibits 94.8% selectivity towards cinnamyl alcohol by the transfer hydrogenation of einnamaldehyde with Pt loading of 2.46% under the optimum conditions of 120 ℃ for 6 h, and 2-propanol as a hydrogen donor. Additionally, the present study demonstrates that a high-efficient and recyclable catalyst can be rapidly separated from the mixture due to its natural magnetism upon the application of magnetic field.展开更多
The catalytic activity of metal catalysts can be modulated by confinement within the channels of carbon nanotubes(CNTs).Here,we show that the product distribution of cinnamaldehyde hydrogenation can be modified by con...The catalytic activity of metal catalysts can be modulated by confinement within the channels of carbon nanotubes(CNTs).Here,we show that the product distribution of cinnamaldehyde hydrogenation can be modified by confinement of Ru nanoparticles in CNTs.A catalyst composed of Ru nanoparticles dispersed on the exterior walls of CNTs gave hydrocinnamaldehyde as product.In contrast,confinement of the Ru nanoparticles within CNT channels facilitated hydrogenation of C=O bonds and complete hydrogenation,and both cinnamyl alcohol and hydrocinnamyl alcohol formed in addition to hydrocinnamaldehyde.High‐resolution transmission electron microscopy,Raman spectroscopy,hydrogen temperature‐programmed reduction,and hydrogen temperature‐programmed desorption were used to investigate the characteristics of the catalysts.The results indicate that the different interactions between the confined Ru nanoparticles and the exterior and interior walls of the CNTs,as well as spatial restriction and enrichment within the narrow channels likely play important roles in modulation of the product distribution.展开更多
基金This work is supported by the National Natural Science Foundation of China （No.51372248, No.51432009 and No.51502297）, Instrument Developing Project of the Chinese Academy of Sciences （No.yz201421）, the CAS/SAFEA International Partnership Program for Creative Research Teams of Chinese Academy of Sciences, China.
文摘A variety of spherical and structured activated charcoal supported Pt/Fe3O4 composites with an average particle size of ~100 nm have been synthesized by a self-assembly method using the difference of reduction potential between Pt （Ⅳ） and Fe （Ⅱ） precursors as driving force. The formed Fe3O4 nanoparticles （NPs） effectively prevent the aggregation of Pt nanocrystallites and promote the dispersion of Pt NPs on the surface of catalyst, which will be favorable for the exposure of Pt active sites for high-efficient adsorption and contact of substrate and hydrogen donor. The electron-enrichment state of Pt NPs donated by Fe304 nanocrystallites is corroborated by XPS measurement, which is responsible for promoting and activating the terminal C=O bond of adsorbed substrate via a vertical configuration. The experimental results show that the activated charcoal supported Pt/Fe3O4 catalyst exhibits 94.8% selectivity towards cinnamyl alcohol by the transfer hydrogenation of einnamaldehyde with Pt loading of 2.46% under the optimum conditions of 120 ℃ for 6 h, and 2-propanol as a hydrogen donor. Additionally, the present study demonstrates that a high-efficient and recyclable catalyst can be rapidly separated from the mixture due to its natural magnetism upon the application of magnetic field.
基金supported by the National Natural Science Foundation of China (21621063,21425312)~~
文摘The catalytic activity of metal catalysts can be modulated by confinement within the channels of carbon nanotubes(CNTs).Here,we show that the product distribution of cinnamaldehyde hydrogenation can be modified by confinement of Ru nanoparticles in CNTs.A catalyst composed of Ru nanoparticles dispersed on the exterior walls of CNTs gave hydrocinnamaldehyde as product.In contrast,confinement of the Ru nanoparticles within CNT channels facilitated hydrogenation of C=O bonds and complete hydrogenation,and both cinnamyl alcohol and hydrocinnamyl alcohol formed in addition to hydrocinnamaldehyde.High‐resolution transmission electron microscopy,Raman spectroscopy,hydrogen temperature‐programmed reduction,and hydrogen temperature‐programmed desorption were used to investigate the characteristics of the catalysts.The results indicate that the different interactions between the confined Ru nanoparticles and the exterior and interior walls of the CNTs,as well as spatial restriction and enrichment within the narrow channels likely play important roles in modulation of the product distribution.
