نتایج جستجو برای: catalyst

تعداد نتایج: 44027  

2016
Richa Baronia Shraddha Tiwari Avanish K. Srivastava Surinder P. Singh Sunil K. Singhal

In the present work we report a facile method for the synthesis of Pt nanoparticles supported reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs) nanocomposite by an in-situ chemical reduction. The incorporation of MWCNTs to rGO leads to decrease in agglomeration between rGO sheets due to π – π interactions and higher loading of Pt nanoparticles. In this process, a mixture o...

Journal: :Physical chemistry chemical physics : PCCP 2012
Kyoung Ju Kim Woong-Ryeol Yu Ji Ho Youk Jinyong Lee

The formation of carbon nanotubes (CNTs) through precipitated carbons emerging from supersaturated metal catalysts is an established mechanism for their growth during the CVD process. Here, the CNT growth mode is determined by the interaction between the substrate and the catalyst nanoparticle, e.g., the tip-growth mode for the weak adhesion between them and the base-growth mode for the strong ...

2008
Kazunori Kakehi Suguru Noda Shigeo Maruyama Yukio Yamaguchi

The relationships among the nominal thickness of Co catalyst, the structure of the catalyst particles, and the structure of carbon nanotubes (CNTs) growing from the catalyst during chemical vapor deposition were investigated. Various morphologies of CNTs such as individuals, random networks parallel to the surface of the substrate (‘grasses’), and vertically-aligned forests of singleand multi-w...

2007
S. J. KORF J. A. ROOS N. A. DE BRUIJN J. G. VAN OMMEN J. R. H. ROSS

Active sites are created on the surface of a Li/MgO catalyst used for the selective oxidation of methane by the gradual loss of carbondioxide from surface carbonate species in the presence of oxygen. Decomposition of the carbonat~ species in the absence of oxygen is detrimental to the activity of the cataIy~t. The active sites'created are not stable but disappear either as a result of reaction ...

2018
Angela J. Murray Ju Zhu Joe Wood Lynne E. Macaskie

Bacteria can fabricate platinum group metal (PGM) catalysts cheaply, a key consideration of industrial processes and waste decontaminations. Biorecovery of PGMs from wastes is promising but PGM leachates made from metallic scraps are acidic. A two-step biosynthesis 'pre-seeds' metallic deposits onto bacterial cells benignly; chemical reduction of subsequent metal from acidic solution via the se...

Journal: :Physical chemistry chemical physics : PCCP 2015
Arya Shafiefarhood Joseph Clay Hamill Luke Michael Neal Fanxing Li

The chemical looping reforming (CLR) process, which utilizes a transition metal oxide based redox catalyst to partially oxidize methane to syngas, represents a potentially efficient approach for methane valorization. The CLR process inherently avoids costly cryogenic air separation by replacing gaseous oxygen with regenerable ionic oxygen (O(2-)) from the catalyst lattice. Our recent studies sh...

2001
E. Chibowski

Catechin belongs to a group of flavonoids, which are present in many fruits and plants. Catechin is often employed in model investigations on antioxidant behavior of flavonoids. Recently also some anti-disease properties of flavonoids were reported. In this paper investigations were carried out on alumina/(+ )-catechin solution system. FTIR spectra were taken for the catechin samples retaken fr...

2014
Giuseppe Trunfio

The deactivation pattern of a “model” Ni/MgO catalyst in the pre-reforming of n-hexane with steam (T, 450 °C; P, 5–15 bar) is reviewed. The influence of the steam-to-carbon ratio (S/C, 1.5–3.5) on the rate of catalyst fouling by coking is ascertained. Catalyst fouling leads to an exponential decay in activity, denoting 1-order dependence of the coking process on active sites availability. Hydro...

2004
Stephan Schwinghammer Rolf Marr Matthäus Siebenhofer

Esterification of acetic acid with methanol with and without heterogeneous catalyst was carried out in compressed carbon dioxide. In the first part of this project the autocatalytic effect of the compressed CO2 on this equilibrium reaction was investigated. The use of high-pressure carbon dioxide, an environmentally benign solvent, will shift the yield towards the desired product methyl acetate...

2009
Daiki Shigeoka Hikaru Katayanagi Kamil Lipert Manfred Ritschel Albrecht Leonhardt Yulia Krupskaya Bernd Büchner Rüdiger Klingeler

In this paper we report on the magnetic properties of singleand multiwalled carbon nanotubes synthesized using different chemical vapour deposition methods and with variety of catalyst materials (ferromagnetic Fe, FeCo and diamagnetic Re). Different methods yield carbon nanotubes with different morphologies and different quantity of residual catalyst material. Catalyst particles are usually enc...

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