Impregnation nanoparticles

Figure 16 illustrates the status of another route to improvement of the cathode performance. Here, a nano-crystalline gadolinia doped ceria catalyst has been added to the electrodes, resulting in improved performance over the comparable reference cells for both LSM/YSZ and LSC/CGO electrodes [29]. Continued development includes investigation of stability of the colloidal impregnated nanoparticles as function of time and temperature. Such nano-stmctured electrodes based on infiltration are expected to play an important role for further improvements of the next generation cell technology. 

Controlled cutting and opening of closed carbon systems Direct applications of CNTs (requires 20-100 nm in length) Inner filling and impregnation of CNTs with metal nanoparticles and complexes... 

For many years, research efforts in materials chemistry have focused on the development of new methods for materials synthesis. Traditional areas of interest have included the synthesis of catalytic, electronic, and refractory materials via aqueous methods (sol-gel and impregnation) and high-temperature reactions [1-3]. More recent strategies have focused on the synthesis of materials with tailored properties and structures, including well-defined pores, homogeneously distributed elements, isolated catalytic sites, comphcated stoichiometries, inorganic/organic hybrids, and nanoparticles [4-13]. A feature... 

Figure 2 schematically presents a synthetic strategy for the preparation of the structured catalyst with ME-derived palladium nanoparticles. After the particles formation in a reverse ME [23], the hydrocarbon is evaporated and methanol is added to dissolve a surfactant and flocculate nanoparticles, which are subsequently isolated by centrifugation. Flocculated nanoparticles are redispersed in water by ultrasound giving macroscopically homogeneous solution. This can be used for the incipient wetness impregnation of the support. By varying a water-to-surfactant ratio in the initial ME, catalysts with size-controlled monodispersed nanoparticles may be obtained. 

Figure 3. Schematic representation of the selective synthesis of metal nanowires and nanoparticles by the Sintering Controlled Synthesis approach, (a) Mesoporous silica, (b) impregnation of mesoporous silica with metal ions, (c) addition of water/alcohol vapors and UV-irradiation, or wet H2-reduction, (d) formation of metal nanowires, (e) dry H2-reduction, (f) formation of metal nanoparticles.

While there are extensive reviews of organosols and the catalysts therefrom in the literature, hy-drosols are relatively unknown in spite of the promising electrocatalysts that can emerge from them. Hydrosols of mono-, bi- and multimetallic nanoparticles as isolable precursors for producing supported metal catalyst are an economically beneficial alternative to the traditional wet impregnation of active metal components on carrier surfaces [25],... 

Point of Use Wastewater Treatment Using Agglomerated Nanoparticles of Titanium (IV) oxide and Blotter Paper Impregnated with Silver Nanoparticles in Colum Mode... 

Pristine CNTs are chemically inert and metal nanoparticles cannot be attached [111]. Hence, research is focused on the functionalization of CNTs in order to incorporate oxygen groups on their surface that will increase their hydrophilicity and improve the catalyst support interaction (see Chapter 3) [111]. These experimental methods include impregnation [113,114], ultrasound [115], acid treatment (such as H2S04) [116— 119], polyol processing [120,121], ion-exchange [122,123] and electrochemical deposition [120,124,125]. Acid-functionalized CNTs provide better dispersion and distribution of the catalysts nanoparticles [117-120],... 

Fig. 15.14 Illustration of selective deposition strategies for catalyst nanoparticles (left) on the inner and (right) on the outer surface of CNTs according to Ref. [Ill], For inside deposition the CNTs are (a) impregnated with an ethanolic solution of the metal precursor, followed by washing with distilled water to protect the outer surface, and (c) subsequent drying and final treatment to form the catalyst nanoparticies. For outside deposition the CNTs are (d) impregnated with an organic solvent to block the inner tubule, followed by (e) impregnation with an aqueous solution of the metal precursor and (f) subsequent drying and final treatment.

In addition to surfactant-stabilized colloids, there has been work on forming metal colloids without stabilizers. Lee et al. have shown that direct reduction of mefal chloride salts in tetrahydrofuran with LiBH4 gives small nanoparticles that can be impregnated onto carbon. No further treatment is required after the removal of the solvent. This route was applied to the preparation of PfRu, PtNi, PtMo, and PtW particles. 

Up to now, a variety of non-zeolite/polymer mixed-matrix membranes have been developed comprising either nonporous or porous non-zeolitic materials as the dispersed phase in the continuous polymer phase. For example, non-porous and porous silica nanoparticles, alumina, activated carbon, poly(ethylene glycol) impregnated activated carbon, carbon molecular sieves, Ti02 nanoparticles, layered materials, metal-organic frameworks and mesoporous molecular sieves have been studied as the dispersed non-zeolitic materials in the mixed-matrix membranes in the literature [23-35]. This chapter does not focus on these non-zeoUte/polymer mixed-matrix membranes. Instead we describe recent progress in molecular sieve/ polymer mixed-matrix membranes, as much of the research conducted to date on mixed-matrix membranes has focused on the combination of a dispersed zeolite phase with an easily processed continuous polymer matrix. The molecular sieve/ polymer mixed-matrix membranes covered in this chapter include zeolite/polymer and non-zeolitic molecular sieve/polymer mixed-matrix membranes, such as alu-minophosphate molecular sieve (AlPO)/polymer and silicoaluminophosphate molecular sieve (SAPO)/polymer mixed-matrix membranes. 

The traditional method for generating nanoparticles in mesoporous materials includes a wet impregnation process, followed by treatment with heat, reducing reagents or oxidation. This method could be applied to a lot of metals [43, 61] or metal oxides [50, 59], Other... 

---