Catalyst characterization, aims

We have already mentioned that fundamental studies in catalysis often require the use of single crystals or other model systems. As catalyst characterization in academic research aims to determine the surface composition on the molecular level under the conditions where the catalyst does its work, one can in principle adopt two approaches. The first is to model the catalytic surface, for example with that of a single crystal. By using the appropriate combination of surface science tools, the desired characterization on the atomic scale is certainly possible in favorable cases. However, although one may be able to study the catalytic properties of such samples under realistic conditions (pressures of 1 atm or higher), most of the characterization is necessarily carried out in ultrahigh vacuum, and not under reaction conditions. 

What are the aims of catalyst characterization in the context of (a) industrial catalysis and (b) fundamental research ... 

Heterogeneous Catalysis Aim of Catalyst Characterization Spectroscopic Techniques Research Strategies... 

In this chapter we present four case studies to illustrate catalyst characterization from a problem-oriented approach. The intention is to show what can be achieved by using combinations of techniques. The selected studies all have the aim of determining the composition and the structure of a catalyst or a catalytic surface in atomic detail. 

In the mentioned studies the selective hydrogenations were made with the aim to obtain kinetical data, and the catalysts characterization was scarce. On the other hand, It is known that metal supported catalysts exhibit important particle size and support effects in the selectivity patterns (ref. 7). 

Heterogeneous catalysis The aim of catalyst characterization Spectroscopic techniques Research strategies... 

HNO3 functionalized carbons are used as supports for the preparation of bimetallic Pd-Bi/C catalysts. The aim is to take advantage of the oxygenated surface functions introduced on the carbon, which are expected to act as anchoring sites. Two neutral coordination complexes were selected to incorporate the two metals onto differently functionalized caibon supports. The grafted samples are then submitted to an activation treatment and characterized by SEM, XRD and XPS. It appears that the order of incorporation strongly influences the surface properties of the catalysts and thus modifies their activity in the oxidation of glucose. 

In this study butyl acetate (AcOBu) was hydrogenolysed to butanol over alumina supported Pt, Re, RePt and Re modified SnPt naphtha reforming catalysts both in a conventional autoclave and a high throughput (HT) slurry phase reactor system (AMTEC SPR 16). The oxide precursors of catalysts were characterized by Temperature-Programmed Reduction (TPR). The aim of this work was to study the role and efficiency of Sn and Re in the activation of the carbonyl group of esters. 

The aim of this study is to develop model reaction for the characterization of the acidity and basicity of various transition aluminas, the experimental conditions being close to that for catalysis use. Among various model reactions, the transformation of cyclopentanol and cyclohexanone mixture was chosen for this work. Indeed, this reaction was well known for estimating simultaneously the acid-base properties of oxide catalysts [1], Two reactions take place the hydrogen transfer (HT) on basic sites and the alcohol dehydration (DEH) on acid sites. The global reaction scheme is shown in Figure 1. 

The objective of this work is to synthesize and characterize zeolite-bentonite hybrid catalysts and perform test reactions in the pyrolysis of woody biomass in a dual-fluidized bed reactor. The aim is to produce catalytic materials which have good mechanical strength and are still able to de-oxygenate the pyrolysis oil. 

Spectroscopy in Catalysis is an introduction to the most important analytical techniques that are nowadays used in catalysis and in catalytic surface chemistry. The aim of the book is to give the reader a feeling for the type of information that characterization techniques provide about questions concerning catalysts or catalytic phenomena, in routine or more advanced applications. 

Operando methodology aims to define and characterize structure/function relationships which must be interfaced with rate and dynamics measurements of the elementary steps. Recent years have shown a marked increase in the presence of spectroscopic investigations of catalytic reactions in literature (see Catalysis Today, 113 issues 1-2). For example, operando techniques were used to determine the temperature stability range of two NOx reduction catalyst types, (NH4)[Co(H20)2]Ga(P04)3 vi. (NH4)[Mn(H20)2]Ga(P04)3. Fig. 5 shows that the catalyst with manganese changes in structural stability around 673 K. Inspection of the catalyst with cobalt shows that there is no structure modification at a temperature below 673 K. 

With the aim to study the characteristics of VPO catalysts in the course of butane oxidation to maleic anhydride together with a simultaneous evaluation of the catalytic performance, we have used Raman spectroscopy which is a very sensitive probe for determining the presence of V0P04-like entities together with (VO)2P207. An in situ Laser Raman Spectroscopy (LRS) cell was built in our laboratory (6). In the corresponding publication (6 ), the preparation and the characterization by XRD, Ip... 

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