نتایج جستجو برای: catalyst nanoparticles

تعداد نتایج: 147722  

Journal: :journal of nanostructures 2015
h. khojasteh v. mirkhani m. moghadam s. tangestaninejad i. mohammadpoor-baltork

palladium is the best metal catalyst for suzuki cross coupling reaction for synthesize of unsymmetrical biaryl compounds. but its high cost limits its application in wide scale. using of nanoscale particles as active catalytic cites is a good approach for reducing needed noble metal. by loading precious nanoparticles on magnetic nanocores as a support, recycling and reusing of catalyst will be ...

2012
Raed Abu-Reziq

The synthesis of magnetically separable quasi-homogeneous base catalyst and heterogeneous base catalyst is described. The quasi-homogeneous catalyst is achieved by supporting silane monomers functionalized with different amine groups directly on the surface of magnetite nanoparticles. The heterogeneous catalyst is prepared via a sol-gel process in which silane monomers containing different amin...

2015
Jiacheng Wang Simon A. Kondrat Yingyu Wang Gemma L. Brett Cicely Giles Jonathan K. Bartley Li Lu Qian Liu Christopher J. Kiely Graham J. Hutchings

The control over both the dispersion and the particle size distribution of supported precious metal nanoparticles used in heterogeneous catalysts is of paramount importance. Here, we demonstrate the successful formation of highly accessible and well dispersed gold−palladium nanoparticles, stabilized with two-dimensional graphene oxide, that itself is dispersed by intercalated titania particles ...

2007
Fabing Su Fang Yin Lee Lu Lv Jiajia Liu Xiao Ning Tian Xiu Song Zhao

Since the discovery of ruthenium as a catalyst for hydrogenation reactions, Ru catalysts have been widely used in the chemical, petrochemical, food, and pharmaceutical industries, and in energy-conversion technologies. The scope of homogeneous Ru catalysts has been well-illustrated recently. However, heterogeneous catalysts can be preferable from both industrial and environmental perspectives. ...

2015
Er-Xiong Ding Jing Wang Hong-Zhang Geng Wen-Yi Wang Yan Wang Ze-Chen Zhang Zhi-Jia Luo Hai-Jie Yang Cheng-Xiong Zou Jianli Kang Lujun Pan

Y-junction carbon nanocoils (Y-CNCs) were synthesized by thermal chemical vapor deposition using Ni catalyst prepared by spray-coating method. According to the emerging morphologies of Y-CNCs, several growth models were advanced to elucidate their formation mechanisms. Regarding the Y-CNCs without metal catalyst in the Y-junctions, fusing of contiguous CNCs and a tip-growth mechanism are consid...

Journal: :Chemical communications 2012
Kyu Hyung Lee Byeongno Lee Kyu Reon Lee Mi Hye Yi Nam Hwi Hur

A dual catalyst containing Pd and CuFe(2)O(4) nanoparticles in a silica shell exhibits >98% conversion of arylacetylenes to related styrenes with selectivity greater than 98%, which are better than those obtained using a commercial Lindlar catalyst. The excellent synergy was likely a result of the proximal interaction between Pd and CuFe(2)O(4) nanoparticles.

2002
Hee Cheul Choi Dunwei Wang Ali Javey Qian Wang Marco Rolandi Hongjie Dai

Iron containing nanoparticles are found to spontaneously form on hydroxylated SiO2 substrates when immersed in a freshly mixed aqueous solution of FeCl3 and hydroxylamine. Upon calcination, a submonolayer of uniformly distributed iron oxide nanoparticles can be derived and used to catalyze the growth of single-walled carbon nanotubes by chemical vapor deposition. This simple method affords clea...

Journal: :Dalton transactions 2010
Claudine Rangheard César de Julián Fernández Pim-Huat Phua Johan Hoorn Laurent Lefort Johannes G de Vries

The use of non-supported Fe nanoparticles in the hydrogenation of unsaturated C-C bonds is a green catalytic concept at the frontier between homogeneous and heterogeneous catalysis. Iron nanoparticles can be obtained by reducing Fe salts with strong reductants in various solvents. FeCl(3) reduced by 3 equivalents of EtMgCl forms an active catalyst for the hydrogenation of a range of olefins and...

2016
Zhongbin Zhuang Stephen A. Giles Jie Zheng Glen R. Jenness Stavros Caratzoulas Dionisios G. Vlachos Yushan Yan

The development of a low-cost, high-performance platinum-group-metal-free hydroxide exchange membrane fuel cell is hindered by the lack of a hydrogen oxidation reaction catalyst at the anode. Here we report that a composite catalyst, nickel nanoparticles supported on nitrogen-doped carbon nanotubes, has hydrogen oxidation activity similar to platinum-group metals in alkaline electrolyte. Althou...

Journal: :Physical review letters 2012
M Diarra A Zappelli H Amara F Ducastelle C Bichara

Optimized growth of single wall carbon nanotubes requires full knowledge of the actual state of the catalyst nanoparticle and its interface with the tube. Using tight binding based atomistic computer simulations, we calculate carbon adsorption isotherms on nanoparticles of nickel, a typical catalyst, and show that carbon solubility increases for smaller nanoparticles that are either molten or s...

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