Co-reporter:Yuanfeng Xu;Meng Wang;Bo Feng;Ziyang Li;Yuanhua Li;Hexing Li
Catalysis Science & Technology (2011-Present) 2017 vol. 7(Issue 24) pp:5838-5842
Publication Date(Web):2017/12/11
DOI:10.1039/C7CY01954H
Microwave-assisted one-pot dynamic kinetic resolution of aromatic secondary alcohols is successfully conducted by using a recyclable chemoenzymatic catalyst combination. This design concept will attract more attention in the foreseeable future for the synthesis of chiral drugs and their building blocks.
Co-reporter:Liang Xu, Wei Wei, Hexing Li, and Hui Li
ACS Catalysis 2014 Volume 4(Issue 1) pp:251
Publication Date(Web):December 11, 2013
DOI:10.1021/cs400853u
In this paper, one-pot dextrin hydrolysis to glucose and the subsequent glucose hydrogenation to sorbitol is successfully conducted by using amyloglucosidase and Ru–B amorphous alloy highly dispersed onto the ordered mesoporous silica encapsulated by a porous silica shell. The porous outer silica shell prevents the larger amyloglucosidase and colloidal hydrolysis substances from contacting Ru–B, which avoids the poisoning effect on each other. Meanwhile, the small glucose can directly access the Ru–B cores through the pores within the silica shells, and the produced sorbitol can readily exit through these pores. Thus, both the amyloglucosidase-aided dextrin hydrolysis and the Ru–B-catalyzed glucose hydrogenation proceed efficiently in bulk solution and inside the chamber, respectively, leading to high sorbitol yield and strong durability. The catalyst design concept used in such a yolk-shell structured configuration opens a new avenue for the development of a highly efficient catalyst system for one-pot cascade reactions containing incompatible parameters.Keywords: amorphous alloy catalyst; biomass conversion; hydrogenation; hydrolysis; sorbitol
Co-reporter:W. Wei, Y. Zhao, S. C. Peng, H. Y. Zhang, Y. P. Bian, H. X. Li and H. Li
Journal of Materials Chemistry A 2014 vol. 2(Issue 45) pp:19253-19259
Publication Date(Web):29 Sep 2014
DOI:10.1039/C4TA04533E
In this paper, we develop a simple vesicle-assisted chemical reduction approach for synthesizing hollow Ni–Co–B nanospheres. With various characterization techniques, the resulting Ni–Co–B nanospheres are identified as amorphous alloys with a hollow chamber. Coexistence of NiII and CoII species plays a significant role in fabricating hollow nanospheric structures, because only solid nanoparticles can be obtained in the presence of a mono-metallic precursor. During liquid-phase hydrogenation of 2-ethyl-2-hexenaldehyde, hollow Ni–Co–B catalyst displays significant bi-site catalysis from bimetals and delivers much greater activity as well as better selectivity than associated with the dense Ni–Co–B catalyst. Additionally, this catalyst is also easily handled in liquid-phase reactions due to its lower density and magnetic property. The material design concept presented in this work opens a new avenue for the development of hollow non-noble metallic nanospheres and will draw more attention in the foreseeable future.
Co-reporter:Wei Wei, Yu Zhao, Shichao Peng, Haoyang Zhang, Yipeng Bian, Hexing Li, and Hui Li
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 23) pp:20851
Publication Date(Web):November 18, 2014
DOI:10.1021/am5052608
In this paper, we develop a facile strategy for fabricating a yolk–shell structured catalytic system that consists of a core made of Ru supported on mesoporous carbon, which is encaged within a silica shell that has ordered radial mesochannels. A region-selective etching mechanism for the formation of the yolk–shell nanoarchitectures is proposed based on the stronger adsorption ability of the carbon core for etching agent than that of the silica shell for etching agent. By combining such material with amyloglucosidase, one-pot hydrolysis–hydrogenation of dextrin to sorbitol can be conducted, delivering enhanced efficiency and showing great promise for biomass conversion applications.Keywords: biomass conversion; enzymatic catalysis; mesoporous material; metallic catalysis; sorbitol; yolk−shell nanostructure
Co-reporter:Jinqiang Ma, Liang Xu, Lei Xu, Hao Wang, Sen Xu, Hexing Li, Songhai Xie, and Hui Li
ACS Catalysis 2013 Volume 3(Issue 5) pp:985
Publication Date(Web):April 9, 2013
DOI:10.1021/cs400059n
In this paper, uniform Co–B amorphous alloy nanospheres with an average particle size of 50 nm were synthesized by chemical reduction of cobalt ion with borohydride in aqueous solution containing Bu4PBr and KCl. Then, Pd was introduced into this system by galvanic replacement reaction (GRR) between Co and Na2PdCl4. Pd/Co–B catalysts with different Pd content could be obtained via adjusting the amount of Na2PdCl4 in reaction mixture. The crystal structure, morphology, and surface electronic state of as-prepared catalysts were characterized by XRD, TEM, XPS, and H2-TPD. During the liquid-phase hydrogenation of 2-ethyl-2-hexenaldehyde, the as-prepared Pd/Co–B catalysts exhibited extremely active and more selectivity to 2-ethyl-1-hexanol than the monometallic Pd and Co–B amorphous alloy, showing potential application in industry. The enhanced performances could be attributed to the highly dispersed Pd on the surface of Co–B prepared by GRR and the synergetic effect between Pd and Co.Keywords: 2-ethyl-1-hexanol; 2-ethyl-2-hexenaldehyde; bimetallic catalyst; galvanic replacement reaction; hydrogenation; Pd/Co−B
Co-reporter:Ye Xu, Jinqiang Ma, Yuanfeng Xu, Lei Xu, Liang Xu, Hexing Li and Hui Li
RSC Advances 2013 vol. 3(Issue 3) pp:851-858
Publication Date(Web):13 Nov 2012
DOI:10.1039/C2RA22832G
Porous silica-supported metallic Pd catalysts were prepared in three steps: (1) synthesis of oleylamine-capped Pd nanoparticles, (2) silica polymerization around the oleylamine-capped Pd in a water-in-oil microemulsion system and (3) removal of the capping agent through calcination. With the characterization of transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and N2 physisorption, the resultant 3 nm Pd nanoparticles were identified to be homogenously encapsulated within 10 nm-thick porous silica shells. During the oxidation of CO at 443 K, the as-prepared Pd@SiO2-673 delivered a turnover frequency up to 33 times greater than that associated with the reference Pd/SiO2-673 catalyst prepared by a conventional immobilization method. Meanwhile, the as-prepared Pd@SiO2-673 also exhibited significantly improved stability for a continuous reaction of 576 h than the control catalyst. The remarkable enhancement of the catalytic performance was found to depend on the core-shell configuration. The Pd particle cores have a small size (3 nm), contributing to weakening the strength of CO adsorption and thus enhancing catalytic activity. On the other hand, the porous silica shells allow the reactants to penetrate into the core-shell structured Pd@SiO2 composite and thus increase the accessibility of the Pd cores. Furthermore, they are separate Pd nanoparticles and therefore improve the thermal stability.
Co-reporter:Zhonghong Zhu, Jinqiang Ma, Liang Xu, Lei Xu, Hexing Li, and Hui Li
ACS Catalysis 2012 Volume 2(Issue 10) pp:2119
Publication Date(Web):August 31, 2012
DOI:10.1021/cs300472p
Control of the size and morphology of metallic nanomaterials enables mastery of their properties to enhance their catalytic performances. In this work, uniform Co–B amorphous alloy nanoparticles were synthesized by a simple chemical reduction of [CoX4]− with BH4– in the presence of Bu4P+. With the characterization of X-ray diffraction, selective area electronic diffraction, X-ray photoelectron spectroscopy, differential scanning calorimetry, and transmission electron microscopy, the resulting Co–B spherical nanoparticles were identified to be amorphous alloys in an average particle size around 55 nm. The synergistic effect of the halide anion and Bu4P+ cation is essential for the formation of monodisperse and uniform spherical nanoparticles. During the Heck-type carbon–carbon coupling reactions and the hydrogenation of butyraldehyde to n-butanol, the as-synthesized Co–B catalyst was extremely active compared with the conventional Co–B obtained via the direct reduction of cobalt ions with BH4– in aqueous solution. In addition, the as-prepared Co–B amorphous alloy also exhibited recyclability during the hydrogenation of butyraldehyde due to better thermal stability, which was related to the higher surface B content and the uniform particle size.Keywords: amorphous alloy; Co−B; Heck reaction; high stability; hydrogenation
Co-reporter:Hui Li, Zhonghong Zhu, Fang Zhang, Songhai Xie, Hexing Li, Ping Li, and Xinggui Zhou
ACS Catalysis 2011 Volume 1(Issue 11) pp:1604
Publication Date(Web):October 6, 2011
DOI:10.1021/cs200351p
A hydrothermally stable metal–organic framework, MIL-101, was used as support for a metallic Pd nanoparticle catalyst. With the characterization of X-ray photoelectron spectroscopy, X-ray diffraction, N2 physisorption, scanning electron microscopy, transmission electron microscopy, and CO chemisorption, the resulting Pd nanoparticles were identified to be confined in the cages of MIL-101. During the one-pot indole synthesis between 2-iodoaniline and phenylacetylene in water, the as-prepared Pd catalyst was more active and stable than the metallic Pd nanoparticles supported on MCM-41. The enhanced catalytic properties were found to depend on both the texture and the surface chemistry of the MIL-101 support.Keywords: clean organic synthesis; domino indole synthesis; MOFs; palladium; water-medium;
Co-reporter:Hui Li, Hong Lin, Ying Hu, Hexing Li, Ping Li and Xinggui Zhou
Journal of Materials Chemistry A 2011 vol. 21(Issue 45) pp:18447-18453
Publication Date(Web):19 Oct 2011
DOI:10.1039/C1JM11461A
Hollow Pt-Ni alloy nanospheres with tunable chamber size and shell thickness are prepared through a modified galvanic replacement approach. The strategy for fabricating such hollow alloys is discussed based on systematic characterization. During the liquid-phase p-chloronitrobenzene hydrogenation to p-chloroaniline, these hollow alloy materials exhibit much higher activity, greatly enhanced selectivity and better durability than the solid Pt nanoparticles. Of particular interest is the controllable shell thickness, which allows for tuning of catalytic activity.
Co-reporter:Hui Li;Fuxing Dong;Mingwen Xiong;Hexing Li;Ping Li;Xinggui Zhou
Advanced Synthesis & Catalysis 2011 Volume 353( Issue 11-12) pp:2131-2136
Publication Date(Web):
DOI:10.1002/adsc.201100064
Abstract
A novel indium-boron (In–B) amorphous alloy was prepared by chemical reduction of indi- um(III) ions [In3+] with borohydride [BH4−] in aqueous solution and was applied to the water-medium Barbier-type allylation reactions. A variety of allyl halides could be efficiently added to aldehydes or ketones in water. Additionally, the as-prepared In–B exhibits much higher activity than the commercial In powder and the crystallized In–B owing to the high surface area, the unique amorphous alloy structure, and the high electron density on the In active sites resulting from the strong electronic interaction between the metal In and the alloying B. The yield of target product over the In–B amorphous alloy was similar to that obtained on the homogeneous Pd(II) organometallic catalyst, showing good potential in practical application.
Co-reporter:Hui Li, Zhonghong Zhu, Jun Liu, Songhai Xie and Hexing Li
Journal of Materials Chemistry A 2010 vol. 20(Issue 21) pp:4366-4370
Publication Date(Web):26 Apr 2010
DOI:10.1039/B926347K
The synthesis and characterization of hollow Pd–Co bimetallic nanospheres are reported. During Sonogashira-type coupling reactions between aryl halides and terminal alkynes in aqueous medium, these hollow materials exhibited much higher activity than the solid counterpart nanoparticles. Moreover, the catalytic activity could be adjusted via changing the catalyst composition. The enhanced activity was attributed to both the hollow chamber structure and the promotional effect of Co-dopants, which provided more Pd active sites for the reactants.
Co-reporter:Hui Li, Zhonghong Zhu, Hexing Li, Ping Li, Xinggui Zhou
Journal of Colloid and Interface Science 2010 Volume 349(Issue 2) pp:613-619
Publication Date(Web):15 September 2010
DOI:10.1016/j.jcis.2010.06.009
Hollow Pd–Fe nanospheres were fabricated through a vesicle-assisted chemical reduction method. With the characterization of X-ray diffraction, selected area electron diffraction, X-ray photoelectron spectroscopy, scanning electron micrography, transmission electron micrography, and N2 physisorption experiment, the resulting Pd–Fe material was identified to be hollow spherical with mesoporous shell. During aqueous Sonogashira-, Heck-, and Ullmann-type coupling reactions of aryl halide, the as-prepared hollow Pd–Fe nanospheres exhibited much higher activity than the dense counterpart nanoparticles. The enhanced reactivity was attributed to both the hollow chamber structure and the promotional effect of Fe-dopants, which provided more Pd active sites for the reactants. Moreover, this hollow material displayed other advantages such as low-cost, recyclability and easy experimental handling.Graphical abstractHollow Pd–Fe nanospheres are fabricated using vesicle template, which are easier to handle and exhibit enhanced catalytic reactivity in aqueous C–C coupling reactions than their dense counterparts.Research highlights► Hollow Pd–Fe nanospheres can be easily fabricated through a vesicle template. ► Hollow Pd–Fe nanospheres exhibit enhanced catalytic reactivity in aqueous C–C coupling reactions. ► Hollow Pd–Fe nanospheres are easily handled in liquid-phase reaction due to its lower density. ► Hollow Pd–Fe nanospheres can be easily recovery due to its magnetic property.
Co-reporter:Hui Li, Ye Xu, Jun Liu, Qingfei Zhao, Hexing Li
Journal of Colloid and Interface Science 2009 Volume 334(Issue 2) pp:176-182
Publication Date(Web):15 June 2009
DOI:10.1016/j.jcis.2009.02.046
Ni–B nanospheres were synthesized through chemical reduction of nickel ions with borohydride in an emulsion system comprised of cyclohexylamine, polyethylene glycol, and water. With the characterization of X-ray diffraction, selective area electronic diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy, the resulting hollow Ni–B nanospheres were identified to be amorphous alloys with a hollow chamber. Cyclohexylamine played a significant role in fabricating hollow Ni–B nanospheres, because only solid nanoparticles were obtained in the absence of cyclohexylamine. Polyethylene glycol also had a significant influence on the formation of hollow Ni–B nanospheres, because low yield of hollow nanospheres were achieved without this polymer. During liquid-phase chloronitrobenzene hydrogenation, the as-synthesized Ni–B catalyst exhibited a much higher activity and even better selectivity than the dense Ni–B nanoparticles prepared by direct reduction of nickel ions with borohydride.Hollow Ni–B amorphous alloy nanospheres are fabricated in emulsion system, which exhibits enhanced catalytic performances relative to the dense counterpart, due to the special curved surface with higher Ni dispersion.
Co-reporter:Hui Li;Jun Liu;Haixia Yang ;Hexin Li
Chinese Journal of Chemistry 2009 Volume 27( Issue 12) pp:2316-2322
Publication Date(Web):
DOI:10.1002/cjoc.201090001
Abstract
Co-B amorphous alloy catalysts supported on three kinds of mesoporous silica (common SiO2, MCM-41 and SBA-15) have been systematically studied focusing on the effect of pore structure on the catalytic properties in liquid-phase hydrogenation of cinnamaldehyde to cinnamyl alcohol (CMO). Structural characterization of a series of different catalysts was performed by means of N2 adsorption, X-ray diffraction, transmission electron microscopy, hydrogen chemisorption, and X-ray photoelectron spectroscopy. Various characterizations revealed that the pore structure of supports profoundly influenced the particle size, location and dispersion degree of Co-B amorphous alloys. Co-B/SBA-15 was found more active and selective to CMO than either Co-B/SiO2 or Co-B/MCM-41. The superior catalytic activity could be attributed to the higher active surface area, because most of Co-B nanoparticles in Co-B/SBA-15 were located in the ordered pore channels of SBA-15 rather than on the external surface as found in Co-B/SiO2 and Co-B/MCM-41. Meanwhile, the geometrical confinement effect of the ordered mesoporous structure of SBA-15 was considered to be responsible for the enhanced selectivity to CMO on Co-B/SBA-15, inhibiting the further hydrogenation of CMO to hydrocinnamyl alcohol.
Co-reporter:Hui Li;Yi Wang;Qingfei Zhao;Hexing Li
Research on Chemical Intermediates 2009 Volume 35( Issue 6-7) pp:779-790
Publication Date(Web):2009 September
DOI:10.1007/s11164-009-0097-6
Monodisperse Ru–B amorphous alloy catalysts were synthesized by ultrasound-assisted chemical reduction of (NH4)2RuCl6 with BH4−. With the characterization of X-ray diffraction (XRD), selective area electronic diffraction (SAED), X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM), the resulting Ru–B nanoparticles were identified to be amorphous alloys ranging in size from 2.4 to 4.9 nm. During liquid-phase maltose hydrogenation, the as-synthesized Ru–B catalyst was extremely active compared to the regular Ru–B obtained via the reduction of RuCl3 with BH4−. The Ru–B sample prepared under ultrasonication with 60 W was proven to be the most active catalyst. Its catalytic activity was nearly 11 times that of industrial Raney Ni, and could be used repetitively for more than six times without significant deactivation.
Co-reporter:W. Wei, Y. Zhao, S. C. Peng, H. Y. Zhang, Y. P. Bian, H. X. Li and H. Li
Journal of Materials Chemistry A 2014 - vol. 2(Issue 45) pp:NaN19259-19259
Publication Date(Web):2014/09/29
DOI:10.1039/C4TA04533E
In this paper, we develop a simple vesicle-assisted chemical reduction approach for synthesizing hollow Ni–Co–B nanospheres. With various characterization techniques, the resulting Ni–Co–B nanospheres are identified as amorphous alloys with a hollow chamber. Coexistence of NiII and CoII species plays a significant role in fabricating hollow nanospheric structures, because only solid nanoparticles can be obtained in the presence of a mono-metallic precursor. During liquid-phase hydrogenation of 2-ethyl-2-hexenaldehyde, hollow Ni–Co–B catalyst displays significant bi-site catalysis from bimetals and delivers much greater activity as well as better selectivity than associated with the dense Ni–Co–B catalyst. Additionally, this catalyst is also easily handled in liquid-phase reactions due to its lower density and magnetic property. The material design concept presented in this work opens a new avenue for the development of hollow non-noble metallic nanospheres and will draw more attention in the foreseeable future.
Co-reporter:Hui Li, Hong Lin, Ying Hu, Hexing Li, Ping Li and Xinggui Zhou
Journal of Materials Chemistry A 2011 - vol. 21(Issue 45) pp:NaN18453-18453
Publication Date(Web):2011/10/19
DOI:10.1039/C1JM11461A
Hollow Pt-Ni alloy nanospheres with tunable chamber size and shell thickness are prepared through a modified galvanic replacement approach. The strategy for fabricating such hollow alloys is discussed based on systematic characterization. During the liquid-phase p-chloronitrobenzene hydrogenation to p-chloroaniline, these hollow alloy materials exhibit much higher activity, greatly enhanced selectivity and better durability than the solid Pt nanoparticles. Of particular interest is the controllable shell thickness, which allows for tuning of catalytic activity.
Co-reporter:Hui Li, Zhonghong Zhu, Jun Liu, Songhai Xie and Hexing Li
Journal of Materials Chemistry A 2010 - vol. 20(Issue 21) pp:NaN4370-4370
Publication Date(Web):2010/04/26
DOI:10.1039/B926347K
The synthesis and characterization of hollow Pd–Co bimetallic nanospheres are reported. During Sonogashira-type coupling reactions between aryl halides and terminal alkynes in aqueous medium, these hollow materials exhibited much higher activity than the solid counterpart nanoparticles. Moreover, the catalytic activity could be adjusted via changing the catalyst composition. The enhanced activity was attributed to both the hollow chamber structure and the promotional effect of Co-dopants, which provided more Pd active sites for the reactants.
![3H-Indolium, 2-[5-[1-[6-[(2,5-dioxo-1-pyrrolidinyl)oxy]-6-oxohexyl]-1,3-dihydro-3,3-dimethyl-5-sulfo-2H-indol-2-ylidene]-1,3-pentadien-1-yl]-1-ethyl-3,3-](/data/chemimg/105700/146368-14-1.png)
![3H-Indolium, 2-[5-[1-[6-[(2,5-dioxo-1-pyrrolidinyl)oxy]-6-oxohexyl]-1,3-dihydro-3,3-dimethyl-5-sulfo-2H-indol-2-ylidene]-1,3-pentadien-1-yl]-1-ethyl-3,3-](/data/chemimg/105700/146368-14-1_b.png)
