Nanomaterials for Nanoscience and Nanotechnology part 11 pdf

... indi- vidual nanoparticles 141]. This type of information is extremely important for under- standing the role of nanoparticles during catalytic reactions. Electron energy-loss images, formed by selecting ... the center of the particles. Further particle analyses can be performed on this type of ªcleanº image, yielding information about the size distribution and the composition of the part...

Ngày tải lên: 12/08/2014, 02:23

... can be emitted from the valence band. The difference between Figures 3-23b and 3-23c is the emission of photon in the former and the Auger electron in the latter, and the two processes are complimentary. 62 ... material. Here, E f is the Fermi level, E b the binding energy, and C.B., V.B. and V.L. are the conduction-band minimum, valance- band maximum, and vacuum level, respective...

Ngày tải lên: 12/08/2014, 02:23

... levels, bands are formed. An energy gap between the con- duction band and the valence band would be formed, which is a key factor in deter- Nanomaterials for Nanoscience and Nanotechnology 5 Part ... nanocrystals and emphasize how the struc- tures and the properties are characterized using the techniques presented in the book. Nanomaterials for Nanoscience and Nanot...

Ngày tải lên: 12/08/2014, 02:23

... metal nanoparticles: a) cubocta- hedron, formed by a fcc crystal truncated at (100) and (111 ) atomic planes; b) icosahedron and c) deca- hedron. b) and c) are known as Multiply-Twinned-Particles ... nm and a half width of 1 nm [28]. Powder X-ray diffraction studies were performed using 8.040 keV photons. As nanoparticles diffraction peaks are rather large (FWHM » 5 degrees for the...

Ngày tải lên: 12/08/2014, 02:23

... order in small particles. In the fol- lowing sections we describe the basic process and the special features of EXAFS experiments on nanoparticles, and illustrate these with a particular example. 2.4.2 ... between absorbing and neighbor atoms, and f(k) represents the total photoelectron phase-shift and depends on both photoabsorber and scattering atoms. A(k) is the backscattering...

Ngày tải lên: 12/08/2014, 02:23

... the < ;111 >. (b) Evolution in shapes of a series of (111 ) based nanoparticles as the ratio of {111 } to {100} increases. The beginning particle is bounded by three {100} facets and a (111 ) base, ... 3-3c),  {111 } and  {220} are both trans- ferred with the negative sign, and there is no relative phase change between  {111 } and  {220} , thus, the interferences between ...

Ngày tải lên: 12/08/2014, 02:23

... diffraction and phase effects (Fig. 4-11a), but these nanoparticles can be easily recognized in HAADF images (Fig. 4-11b). 96 Liu Figure 4 -11. BF (a) and HAADF (b) STEM images of Pt nanoparticles ... overlapping discs. The numeral 2 stands for two- beam interference, 3 for three-beam interference, 4 for four-beam interference, and the letter D indi- cates detector positions for...

Ngày tải lên: 12/08/2014, 02:23

... of Nanoparticles 103 Figure 4-16. Intensity and radius data from particles in HAADF and SE images of silver nanoparticles plotted as (intensity) 1/3 against particle radius R. The HAADF and SE ... structure, and composition of metal parti- cles is of primary importance in understanding the synthesis-structure-activity rela- tionships and is essential for a qualitative and quanti...

Ngày tải lên: 12/08/2014, 02:23

... image of a large MgO cube clearly shows flat {001} faces, ter- raced { 011} faces, and the faceted (111 ) face. The { 011} and {111 } surfaces are composed of {001} terraces or facets. intensity distributions ... samples [93, 112 , 114 ]. Figure 4-25 shows an SE image of a MgO particle revealing surface steps, facets, and the var- Scanning Transmission Electron Microscopy of Nanoparti...

Ngày tải lên: 12/08/2014, 02:23

... 3-3c),  {111 } and  {220} are both trans- ferred with the negative sign, and there is no relative phase change between  {111 } and  {220} , thus, the interferences between  {000} ,  {111 } and  {220} give ... amplitudes  {111 } and  {220} of beams {111 } and {220}, respectively, are chosen as two representatives to show the characteristics of Transmission Electron Mic...

Ngày tải lên: 04/06/2014, 15:19