Carbon dynamics accessibility

Note These specifications were developed at Balazs Analytical Laboratory. Abbreviations are defined as follows DRAM, dynamic random access memory VLSI, very-large-scale integration ULSI, ultralarge-scale integration TOC, total oxidizable carbon THM, trihalomethane SEM, scanning electron microscopy and EPI, epifluorescence... 

Most of the catalytic applications of carbon materials deal with their use in processes carried out under dynamic conditions which are very different to those of static systems. In such processes the accessibility to the catalytically active sites or chemical functionalities is especially important because of the short contact times between the reactives and the carbon catalyst and the polymodal distribution of pores that they present [1]. A large proportion of their surface area and chemical surface groups resides in micropores [2] of diameters very close to the molecular dimension of the reactives and/or the products and so the reaction kinetics may be strongly diffusion controlled. 

Accessibility to the chemical surface groups is a very important factor in order to understand the behaviour of activated carbons as adsorbents and catalysts. This factor becomes particularly important if constrictions in the pore-network are present. So dynamic techniques should be used in order to characterise these kinds of materials. 

Nonlinear vibrational spectroscopy provides accessibility to a range of vibrational information that is hardly obtainable from conventional linear spectroscopy. Recent progress in the pulsed laser technology has made the nonlinear Raman effect a widely applicable analytical method. In this chapter, two types of nonlinear Raman techniques, hyper-Raman scattering (HRS) spectroscopy and time-frequency two-dimensional broadband coherent anti-Stokes Raman scattering (2D-CARS) spectroscopy, are applied for characterizing carbon nanomaterials. The former is used as an alternative for IR spectroscopy. The latter is useful for studying dynamics of nanomaterials. 

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