نتایج جستجو برای: porous catalyst

تعداد نتایج: 92382  

2009
W. Weng

For several decades vanadyl pyrophosphate, (VO)2P2O7, has been used commercially as a catalyst for the partial oxidation of n-butane into maleic anhydride (MA) [1]. However due to the moderate specificity to MA production, many research groups still continue to investigate the V-P-O catalyst system with the aim of further improving its overall performance. Now a specialized form of V-P-O cataly...

2013
Bastian Rühle Melari Davies Thomas Bein Christoph Bräuchle

In this article, we discuss how fluorescence microscopy techniques are used to investigate important characteristics of porous silica materials. We start with a discussion of the synthesis, formation mechanism and functionalization of these materials. We then give an introduction to single molecule microscopy and show how this technique can be used to gain deeper insights into some defining pro...

Journal: :Lab on a chip 2013
Sertan Sukas Roald M Tiggelaar Gert Desmet Han J G E Gardeniers

This paper presents a method for the fabrication of integrated porous silica layers in microfluidic channel networks by microfabrication techniques. Porous silica is obtained by anodization of silicon, followed by full conversion of the porous silicon network into porous silica by means of thermal oxidation. A series of experiments were performed with various channel layouts to determine the cr...

The phenomenon of capillary condensation is studied through the weight change of condensed phase in an internally wetted porous pd catalyst pellet during the course of exothermic reacation of cyclohexane hydrogenation in a thermogravimetric analyzer (TGA). The direct measurement of condensed phase indicates that evaporation of condensed phase is confined to the macropores of catalyst pellet at ...

Journal: :Journal of the American Chemical Society 2014
M Hassan Beyzavi Rachel C Klet Samat Tussupbayev Joshua Borycz Nicolaas A Vermeulen Christopher J Cramer J Fraser Stoddart Joseph T Hupp Omar K Farha

Porous heterogeneous catalysts play a pivotal role in the chemical industry. Herein a new Hf-based metal-organic framework (Hf-NU-1000) incorporating Hf6 clusters is reported. It demonstrates high catalytic efficiency for the activation of epoxides, facilitating the quantitative chemical fixation of CO2 into five-membered cyclic carbonates under ambient conditions, rendering this material an ex...

2004
Qingzhi Guo Ralph E. White

A model for the simulation of the steady-state impedance response of a polymer electrolyte membrane fuel cell ~PEMFC! cathode is presented. The catalyst layer of the electrode is assumed to consist of many flooded spherical agglomerate particles surrounded by a small volume fraction of gas pores. Stefan-Maxwell equations are used to describe the multicomponent gas-phase transport occurring in b...

Journal: :Physical chemistry chemical physics : PCCP 2013
Áron Varga Moritz Pfohl Nicholas A Brunelli Marcel Schreier Konstantinos P Giapis Sossina M Haile

Carbon nanotubes have been explored as interconnects in solid acid fuel cells to improve the link between nanoscale Pt catalyst particles and macroscale current collectors. The nanotubes were grown by chemical vapor deposition on carbon paper substrates, using nickel nanoparticles as the catalyst, and were characterized using scanning electron microscopy and Raman spectroscopy. The composite el...

Journal: :Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 2010
Jianbo Wu Zhenmeng Peng Hong Yang

This paper describes a facile solution route to the synthesis of CoCuPt hollow nanoparticles that readily form chain-like structures in solution. The formation of porous CoCuPt nanostructure is through galvanic replacement with cobalt-containing cores as the templates. This approach does not require the further removal of templates and greatly simplifies the synthetic procedures. These porous C...

2006
Matthew R Maschmann Aaron D Franklin Dmitri N Zakharov Eric A Stach Timothy D Sands Timothy S Fisher

Vertical single-walled and double-walled carbon nanotube (SWNT and DWNT) arrays have been grown using a catalyst embedded within the pore walls of a porous anodic alumina (PAA) template. The initial film structure consisted of a SiOx adhesion layer, a Ti layer, a bottom Al layer, a Fe layer, and a top Al layer deposited on a Si wafer. The Al and Fe layers were subsequently anodized to create a ...

2016
M. Wang Y. X. Lu L. T. Liu X. H. Wang

In this paper, we demonstrate a monolithic integrated micro direct methanol fuel cell (μDMFC) for the first time. The monolithic integrated μDMFC combines proton exchange membrane (PEM) and Pt nanocatalysts, in which PEM is achieved by the functionalized porous silicon membrane and 3D Pt nanoflowers being synthesized in situ on it as catalysts. Sulfo groups functionalized porous silicon membran...

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