Scanning transmission microscopy STM

In NSR catalysts, the Ba-Pt interface plays an important role in the storage of NOx, which occurs by the formation of Ba(N03)2. Recent results [95] using scanning transmission microscopy (STM) and a model catalyst formed by deposition of a Ba thin films on Pt(lll) showed that, at room temperature, a film of Ba was formed with few individual Ba atoms, which were locally ordered. Upon annealing, particles are produced, of which atomic resolution is achieved with an atomic spacing consistent with the (111) plane of Ba. 

Surface morphology SEM, TEM, atomic force microscopy (AFM), scanning transmission microscopy (STM)... 

In addition to surface analytical techniques, microscopy, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning tunneling microscopy (STM) and atomic force microscopy (AFM), also provide invaluable information regarding the surface morphology, physico-chemical interaction at the fiber-matrix interface region, surface depth profile and concentration of elements. It is beyond the scope of this book to present details of all these microscopic techniques. 

The use of high-resolution transmission electron microscopy (HRTEM) and scanning tunneling microscopy (STM) to investigate the morphologies of oxides and chlorides and to compare the surface characteristics of dispersed materials, films, and single crystals. 

The above historical remarks might convey a subtle and scattered impression. It is true that any direct evidence has not yet been presented in the sense that monocyclicity is proven by rotationally resolved spectroscopy, NMR spectroscopy, or high-resolution images by scanning tunneling microscopy (STM) or transmission electron microscopy (TEM). 

Because the ACFs are porous carbons that have no significant differences compared with other porous carbons, the techniques used for their characterization are almost the same. Since the porosity in carbons is the responsible for their adsorption properties, the analysis of the different types of pores (size and shape), as weU as the pore size distribution, is very important to foresee the behavior of these porous solids in final applications. We can state that the complete characterization of the porous carbons is complex and needs a combination of techniques, due to the heterogeneity in the chemistry and structure of these materials. There exist several techniques for the analysis of the porous structure, from which we can underline physical adsorption of gases, mercury porosimetry, small-angle neutron and X-ray scattering (SANS and SAXS), transmission and scanning electron microscopy (TEM and SEM), scanning tunnel microscopy (STM), immersion calorimetry, etc. 

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