نتایج جستجو برای: catalysts

تعداد نتایج: 32940  

2012
Feng Guo Zhen Fang

Biodiesel is usually produced by transesterification of vegetable oils or animal fats with chemical catalysts, especially in the presence of strong acidic or basic solutions, such as hydrochloric acid, sulphuric acid, sodium hydroxide, sodium methoxide and potassium hydroxide. Homogeneous alkali catalysts can convert triglycerides to their corresponding fatty acid methyl esters (FAMEs) with hig...

2014
Masakatsu Shibasaki Naoya Kumagai

From the synthetic point of view, organic synthesis via catalytic processes offers many benefits. Catalysis frequently obviates the excessive use of the activating reagents and associated tedious purification processes, thereby offering more environmentally benign synthetic processes. Furthermore, the specific activation mode of a catalyst allows for highly chemoselective transformations that a...

2017
Mei-xian Wang Fan Xu Qi Liu Hong-fang Sun Rui-hua Cheng Hao He Eric A. Stach Jian Xie

XC72 carbon blacks were treated using a steam-etching technique. Pt catalysts using steam-etched carbon blacks (SECBs) as supports were developed for oxygen reduction reactions in polymer electrolyte fuel cells (PEFCs). The use of the steam-etched carbon blacks as a catalyst support can improve the dispersion uniformity of Pt nanoparticles on the surface of the support and can decrease the Pt p...

2005
W. T. Wallace D. W. Goodman

The optimization of oxide-supported metal clusters as heterogeneous catalysts requires a detailed understanding of the metal cluster–oxide interface. Model catalysts, prepared by deposition of a catalytically active metal onto a thin film oxide support, closely mimic real-world catalysts, yet are amenable to study using surface sensitive techniques. Surface science methods applied to model cata...

2017
Ya-Li Du Xu Wu Qiang Cheng Yan-Li Huang Wei Huang

As a favorably clean fuel, syngas (synthesis gas) production has been the focus of concern in past decades. Substantial literatures reported the syngas production by various catalytic reforming reactions particularly in methane or ethanol reforming. Among the developed catalysts in these reforming processes, Ni-based catalysts from hydrotalcite-like compounds (HTLcs) precursors have drawn consi...

Journal: :Molecules 2010
Radha Narayanan

Since metal nanoparticles have a high surface-to-volume ratio and very active surface atoms, they are very attractive catalysts for a wide variety of organic and inorganic reactions, compared to bulk catalysts. Metal nanoparticles suspended in colloidal solutions and those adsorbed onto bulk supports have been used as catalysts for a wide variety of carbon-carbon bond formation reactions such a...

2003
Jian Xu Calvin H. Bartholomew

Introduction The preparation and characterization of nanophase materials has received considerable attention in recent years, given their potential for improved performance as catalysts, high-strength materials, and semiconductor devices. For example, a recent breakthrough by Sun et al. (1) in the synthesis of highly-dispersed, silica-supported iron-platinum (FePt) bimetallic nanoclusters of co...

2009
Liang Li

Carbon nanotubes (CNTs) have been investigated in recent years as a catalyst support for proton exchange membrane fuel cells. Improved catalyst activities were observed and attributed to metal-support interactions. We report a study on the kinetics of methanol electro-oxidation on CNT supported Pt-Ru alloy nanoparticles. Alloy catalysts with different compositions, Pt53Ru47/CNT, Pt69Ru31/CNT an...

Journal: :Angewandte Chemie 2014
Carl A Denard Hua Huang Mark J Bartlett Lu Lu Yichen Tan Huimin Zhao John F Hartwig

Although chemical and enzymatic catalysts have been combined, reactions in which an organometallic catalyst and a metalloenzyme work cooperatively to create products, which cannot be generated with either catalyst alone or in comparable yields by sequential reactions of the two catalysts, have not been reported. Such reactions are challenging to achieve, in part because the milieu in which thes...

2014
Ritesh Singh Melanie Bordeaux Rudi Fasan

The direct amination of aliphatic C-H bonds represents a most valuable transformation in organic chemistry. While a number of transition metal-based catalysts have been developed and investigated for this purpose, the possibility to execute this transformation with biological catalysts has remained largely unexplored. Here, we report that cytochrome P450 enzymes can serve as efficient catalysts...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید