In situ characterization techniques

Despite the success in modeling catalysts with single crystals and well defined surfaces, there is a clear need to develop models with higher levels of complexity to address the catalytically important issues specifically related to mixed oxide surfaces. The characterization and design of oxide surfaces have not proven to be easy tasks, but recent progress in identification of the key issues in catalytic phenomena on oxide surfaces by in-situ characterization techniques on an atomic and molecular scale brings us to look forward to vintage years in the field. 

The metallic component of HCK catalysts provides hydrogenation, dehydrogenation, hydrogenolysis, and isomerization. The number and nature of reactive hydrogen species created by the interaction of a bifunctional catalyst with hydrogen is not well understood [103], on the other hand, neither the action of those species on the catalytic sites is understood. The main limitation in this understanding is the dynamic character of the interaction however, now that in situ characterization techniques are becoming available, research would soon defeat the limitations. 

In the first half of this introductory chapter the maceral concept has been discussed and the main maceral groups and their important maceral types described. Emphasis has been placed on in situ characterization techniques which rely mostly on microscopy. The rest of this chapter will examine other techniques used for chemical characterization and examine the reactivity of coal macerals in thermal processes. The availability of separated maceral concentrates was a necessary component of the studies which will be described. 

It is clear that vanadium phosphate catalysts are still widely studied although not widely understood. Advances in research methodology, particularly the number of complementary in situ characterization techniques now available, may be able to further the understanding of alkane achvahon and selechve oxidation. This fundamental understanding will be beneficial in the design of new catalyst systems for alkane funchonalizahon and provide new uses for this relatively unreactive, under-uhlized feedstock. 

There are two main difficulties in the development of research work in shock wave chemistry. First, in order to understand the details of chemical reaction induced by shock waves, it is crucial to develop suitable in situ characterization techniques with high time resolution (at least to submicroseconds), high spatial resolution (to mm or, better, to pm), and high resolution for chemical species. These unsatisfied requirements must be met in order to achieve the identified research objectives. Since expensive, sophisticated instmments are necessary, a... 

When the solid electrolytes are used as membranes, there are three different operation modes, as shown in Fig. 3. Id. Mode 1 is under open circuit operation, in which no net current passes through the membrane. The reactor in this mode often serves as a sensor or an in situ characterization technique for catalytic gas-solid reactions under work conditions, named solid electrolyte potentiometry (SEP)... 

Recent Trends in Operando and In Situ Characterization Techniques for Rationai Design ofCataiysts... 

Polymer electrolyte membrane and direct methanol fuel ceO technology Volume 2 In situ characterization techniques for low temperature fuel cells... 

We are convinced that the readership will benefit from the broad scope of this two-volume work, covering as it does a wealth of detailed coverage from fundamental issues to advanced in situ characterization techniques. With methods ranging from the nano- to the macro-scale to investigate effects that are observed in lab-size fuel cells, complete fuel cell stacks and even systems, this work is hoped to be of great use to aryone involved in low-temperature fuel cell research and development. 

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