A Nanoscale Model Catalyst Preparation:  Solution Deposition of Phosphine-Stabilized Gold Clusters onto a Planar TiO2(110) Support

Langmuir ◽  
2001 ◽  
Vol 17 (13) ◽  
pp. 4113-4117 ◽  
Author(s):  
C. C. Chusuei ◽  
X. Lai ◽  
K. A. Davis ◽  
E. K. Bowers ◽  
J. P. Fackler ◽  
...  
2016 ◽  
Vol 17 (4) ◽  
pp. 487-492
Author(s):  
Ye.Yu. Kalishyn ◽  
I.B. Bychko ◽  
Z.V. Kaidanovych ◽  
A.I. Trypolskyi ◽  
P.E. Strizhak ◽  
...  

The production of supported on γ-A12O3 palladium catalysts by colloidal solution deposition method have been improved. Influence of temperature on the structure and dispersion characteristics of supported nanosized palladium particles during catalyst preparation and activation was investigated. It has been shown that at temperatures below 300oC monodisperse particles palladium catalysts are stable. Further temperature increase leads to aggregation of monodisperse metal nanoparticles by the mechanism of reaction-limited aggregation (RLA) to form polydisperse system.


Author(s):  
L.R. Wallenberg ◽  
J.-O. Bovin ◽  
G. Schmid

Metallic clusters are interesting from various points of view, e.g. as a mean of spreading expensive catalysts on a support, or following heterogeneous and homogeneous catalytic events. It is also possible to study nucleation and growth mechanisms for crystals with the cluster as known starting point.Gold-clusters containing 55 atoms were manufactured by reducing (C6H5)3PAuCl with B2H6 in benzene. The chemical composition was found to be Au9.2[P(C6H5)3]2Cl. Molecular-weight determination by means of an ultracentrifuge gave the formula Au55[P(C6H5)3]Cl6 A model was proposed from Mössbauer spectra by Schmid et al. with cubic close-packing of the 55 gold atoms in a cubeoctahedron as shown in Fig 1. The cluster is almost completely isolated from the surroundings by the twelve triphenylphosphane groups situated in each corner, and the chlorine atoms on the centre of the 3x3 square surfaces. This gives four groups of gold atoms, depending on the different types of surrounding.


Author(s):  
James F. Hainfeld ◽  
Frederic R. Furuya

Glutaraldehyde is a useful tissue and molecular fixing reagents. The aldehyde moiety reacts mainly with primary amino groups to form a Schiff's base, which is reversible but reasonably stable at pH 7; a stable covalent bond may be formed by reduction with, e.g., sodium cyanoborohydride (Fig. 1). The bifunctional glutaraldehyde, (CHO-(CH2)3-CHO), successfully stabilizes protein molecules due to generally plentiful amines on their surface; bovine serum albumin has 60; 59 lysines + 1 α-amino. With some enzymes, catalytic activity after fixing is preserved; with respect to antigens, glutaraldehyde treatment can compromise their recognition by antibodies in some cases. Complicating the chemistry somewhat are the reported side reactions, where glutaraldehyde reacts with other amino acid side chains, cysteine, histidine, and tyrosine. It has also been reported that glutaraldehyde can polymerize in aqueous solution. Newer crosslinkers have been found that are more specific for the amino group, such as the N-hydroxysuccinimide esters, and are commonly preferred for forming conjugates. However, most of these linkers hydrolyze in solution, so that the activity is lost over several hours, whereas the aldehyde group is stable in solution, and may have an advantage of overall efficiency.


2020 ◽  
Vol 1000 ◽  
pp. 257-264
Author(s):  
Bambang Heru Susanto ◽  
Joshua Raymond Valentino Siallagan

Bio-Jet could be produced by the synthesis of vegetable oil through the hydrodeoxygenation, decarboxylation, decarbonization, and catalytic cracking process. Physical characteristics, activities, and selectivity of the catalyst used will determine the rate, conversion, and yield of the reaction that being carried out. This study aims to compare and obtain the best characteristics of NiMoP/γ-Al2O3 catalysts synthesized using two types of preparation, impregnation and microwave polyol methods, which will be used for bio-jet production. The impregnation method takes more than 24 hours for catalyst preparation, while microwave polyols that use microwaves can synthesize catalysts faster. Both catalysts have almost the same loading on the weight of the catalyst, which in the microwave polyol method has a more dispersed promotor and active site, although the crystallinity level is deficient and tends to be amorphous compared to the impregnation method with high crystallinity. In bio-jet synthesis reaction with operating conditions of 5% catalyst loading by comparison to Coconut Oil, 400°C, and 15 bar, the conversion, yield, and selectivity of catalyst impregnation were 91.705%, 47.639%, and 84.511%, while microwave polyol catalysts were 90.296%, 42.752%, and 82.517%, respectively. In conclusion, microwave polyol provides a more effective and efficient preparation method.


1999 ◽  
Vol 121 (30) ◽  
pp. 7081-7089 ◽  
Author(s):  
Allen C. Templeton ◽  
David E. Cliffel ◽  
Royce W. Murray
Keyword(s):  

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 630
Author(s):  
Fayaz Hussain ◽  
Saad Alshahrani ◽  
Muhammad Mujtaba Abbas ◽  
Haris Mahmood Khan ◽  
Asif Jamil ◽  
...  

Slaughterhouse waste is considered to be an emerging issue because of its disposal cost. As an alternative, it would be a great prospect for the bioeconomy society to explore new usages of these leftover materials. As per food safety rules mentioned by EU legislation, all bone waste generated by slaughterhouses ought to be disposed of by rendering. The huge quantity of worldwide bone waste generation (130 billion kilograms per annum) is an environmental burden if not properly managed. The waste animal bones can be efficiently employed as a heterogeneous catalyst to produce biodiesel. This mini review summarized the recent literature reported for biodiesel generation using waste animal bones derived heterogeneous catalyst. It discusses the sources of bone waste, catalyst preparation methods, particularly calcination and its effects, and important characteristics of bones derived catalyst. It suggests that catalysts extracted from waste animal bones have suitable catalytic activity in transesterification of different oil sources to generate a good quality biodiesel.


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