Nano-porous

For this micro reactor version, the microstructured platelets were treated by anodic oxidation to obtain a nano-porous layer and impregnated with precursor solutions in organic solvents to obtain a V205 P205 Ti02 catalyst. 

For this version, the micro structured AlMg3 platelets were coated with silver by CVD in [43], In [44], the platelets were either totally made of silver (as constmction material) or of AlMg3 and then coated by PVD with silver. In the latter version, two sub-versions were made with and without anodic oxidation to a generate nano-porous surface structure. 

Bayati, M.R., Golestani-Fard, F., and Moshfegh, A.Z. (2010) Visible photodecomposition of methylene blue over micro arc oxidized WOj-loaded Ti02 nano-porous layers. Applied Catalysis A General, 382 (2), 322-331. 

Gas diffusion in the nano-porous hydrophobic material under partial pressure gradient and at constant total pressure is theoretically and experimentally investigated. The dusty-gas model is used in which the porous media is presented as a system of hard spherical particles, uniformly distributed in the space. These particles are accepted as gas molecules with infinitely big mass. In the case of gas transport of two-component gas mixture (i = 1,2) the effective diffusion coefficient (Dj)eff of each of the... 

In Figure 3, we have presented the experimentally obtained reciprocal values of (Di )t.ff of oxygen in a sample of the nano-porous hydrophobic material as a function of the total pressure P of gas mixture (02-N2) when the oxygen concentration in the mixture is 21%. From the intercept of the straight line with the ordinate the value of the Knudsen diffusion coefficient can be also determined. It must be underlined that the value of Knudsen diffusion coefficient obtained by these diffusion measurements (2,86.10"2 cm2/s) is in very good coincidence with the value obtained by the gas permeability measurements. 

It can be concluded that the predominating mode of gas transport in the investigated nano-porous hydrophobic material is Knudsen diffusion, so that the diffusion is the main mechanism of gas transport in electrochemical systems based on such material and operating with gaseous reactants. 

Kaisheva A., Iliev I. Gas-transport in nano-porous hydrophobic media, Procedings of the Int. Symposium Micro/nanoscale energy conversion and transport, 2002, April 14 -19, Antalya, Turkey, p. 107. 

In principle the bicontinuous 3-dimensional network structure of MCM-48 would act as a good catalytic support.[7] However, its lower hydrothermal and thermal stability has led to much less application of MCM-48 in catalysis. Recently, a family of mesoporous molecular sieves (denoted as MSU-G) with vesicle-like hierarchical structure, worm-like mesoporous structure and bicontinuous nano-porous silica had been synthesized.[8-10] It was proposed that highly accessible mesoporous materials could be obtained through different synthetic procedure and composition. 

The syntheses of most chiral Mn-salen complexes are simple, and thus their recovery and reuse have not been studied extensively. Only a few studies of epoxidation with a polymer-bound Mn-salen complex or a Mn-salen complex embedded in nano-porous materials as catalyst has been performed. It has been disclosed, however, that the microenvironment provided by the macromolecule adversely affects the asymmetric induction by the Mn-salen catalyst to a considerable extent although reuse of the catalysts for several cycles are realized [68]. 

Feng, K. J., Yang, Y. H Wang, Z. J., Jiang, J. H., Shen, G. L. and Yu, R. Q. (2006), A nano-porous Ce02/Chitosan composite film as the immobilization matrix for colorectal cancer DNA sequence-selective electrochemical biosensor. Talanta, 70(3) 561-565. 

The ratio of effective and bulk diffusivity Dett/D is calculated in two steps. First, the effective diffusivity of the nano-porous material with the porosity 8nano = 0.345 is calculated by the algorithm introduced in Section II.E.l. The effective diffusivity of the nano-porous cube with the size 1 pm and porosity nano = 0.345 displayed in Fig. 15 is i//nano = DctJ/D — (0.112 0.004). 

Then, the effective diffusivity of the macro-porous granular material is evaluated. The transport is again governed by the Fick s equation (23), but diffusion also takes place in the solid phase, which formally represents the nano-porous material, cf. Fig. 15. The diffusion coefficient in the solid phase is Dsohd = i//nanoD — 0.112D, where D is the bulk diffusivity. The concentration field in the macro-porous media is the solution of Eq. (23) with a diffusivity... 

The boundary condition of zero accumulation on the interface between macropores and solid phase is imposed. The effective diffusivity of the porous sample G1 with bimodal pore size distribution is summarized in Fig. 16, where the sample macro-porosity macro is varied on the horizontal axis. This effective diffusivity is compared with a situation where the diffusion transport in nanopores is omitted. The contribution of the transport through the nano-porous solid phase to the total diffusion flux is significant. The calculated effective... 

We note that, as long as effects due to spin diffusion can be neglected, analysis of the full relaxation function (t) can yield information that is not available from the first moments (l/T ) and (7)). For example, it is possible to extract information about the width of the distribution of correlations times governing the /1-process. Recently, such approach was used to elucidate the change of the /1-process coming along with a confinement of a glass former in a nano-porous material.100... 

One-step facile hydrothermal methods can synthesize novel nanoporous Ptdr and Pt on RuO2(110) catalysts for ORR. Pt-free catalysts such as Pd-Co, Pd-Ni, Pd-Cr, Pd-Ta, Co-Ni, and CoPds metal alloys"" " as well as the chalcogenide Ru-S and Ru-Se catalysts" " are believed to be promising candidates. Modem studies on ORR electrocatalysts deal with nano-porous gold particles (10-20 nm) with large specific surface area that reduce... 

Recently, attention have been paid to the properties nano-porous silicon. Canham observed the strong luminescence from porous siliconl. A number of photo-luminescent (PL) and/or electro-luminescent(EL) devices have been reported. Steiner et al. reported not only red/orange luminescence but also green/blue electro luminescence from the devicesI L The quantum confinement or the localized centers at the surface have been reported as the luminescence mechanism. They suggested that the luminescence mechanism depends of the fabrication process of the porous silicon s ll. 

Unlike the layered metal oxides, layer rigidity appear to be a critical factor in the pure sheet silicates. These problems are also overcome by altering the charge density or by preswelling the material. This lack of rigidity in these materials has been thought to result in the generation of three-dimensional nano-porous phases . 

The two-dimensional materials which have been e q)lored as layered precursors for active catalysts include the smectites, hydrotalcites, zirconium phosphates, niobium/titanium and manganese oxides and more recently with the associated interest in the generation of the new hexagonal nano-porous phases, the layered silicates. Each will be dealt with individually in this report. 

J. Rappich and H. J. Lewerenz, Photo and potential controlled nano porous silicon formation on N silicon An in-situ FTIR investigation. Thin Solid Films 276, 25, 19%. 

Rao, M.B. and Sircar, S. Performance and pore size characterization of nano-porous carbon membranes for gas separation. Journal of Membrane Science, 1996, 110, 109. 

A model for the nano-structural evolution of Raney-type nickel catalysts (widely used in hydrogenation reactions) from the constituent intermetallic phases present in nickel-aluminium precursor alloys is presented here. Nano-porous nickel catalysts are prepared via a caustic leaching process where the NiAl alloy powder (typically 50-50 at.%) is immersed in concentrated NaOH solution in order to leach away the aluminium present to leave a highly-porous nickel catalyst (often referred to as spongy nickel). 

Firstly, a kinetic Monte Carlo (kMC) [8] for the nano-structural evolution of so-called spongy nickel from the constituent intermetallic phases present in nickel-aluminium precursor alloys is described. Experimental data concerning nano-porous nickel catalyst powder used in this paper are derived from leached NiAl alloy powder produced via a spray-atomization route rather than the conventional cast-and-crushed route. 

In its role as a catalyst, the surface condition of the as-leached nickel nanostructure is highly important. In particular, the sites occupied on the surface of the catalyst by any residual aluminium atoms are of interest. In order to investigate the surface configuration of as-leached surfaces a Metropolis Monte Carlo (MMC) model is subsequently applied. As a starting point the MMC model exploits the nano-porous structure already predicted by the kMC approach. The MMC model aims to simulate the appearance of Al-rich surface configurations that are routinely observed in experiment. 

Once the BKL algorithm is applied Al atoms are progressively removed (at a rate that decreases with time) (8). Simultaneously, adatom diffusion of Ni results leads to the development of a nano-porous structure. 

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