Morphological measurements disperse morphology

In preliminary tests, melt mixed blends of PP and LCP were processed at six different temperatures (Tcyi 230, 240, 250, 260, 270, and 280°C) with a Brabender Plasti-Corder PLE 651 laboratory single-screw extruder. The measured melt temperatures were about 10°C higher than the cylinder temperatures (Tcyi). The objective was to study the influence of temperature on the size and shape of the dispersed LCP phase. Two different polypropylenes were used to ascertain the effect of the viscosity of the matrix on the final morphology. Different draw ratios were obtained by varying the speed of the take-up machine. 

AOTF w/c RMs bearing the silver, silver iodide and silver sulfide nanoparticles were depressurized slowly and the nanoparticles in the cell were collected and re-dispersed in ethanol. Finally, the sample grids for the TEM (FEl TECNAl G ) measurements were prepared by placing a drop of ethanolic dispersion of nanoparticles on the copper grid. The morphology and size distribution of the silver, silver iodide, and silver sulfide nanoparticles were determined by TEM at an operation voltage of 200kV. The crystallinity of the silver, silver iodide, and silver sulfide nanoparticles was studied by electron diffraction techniques. 

Permeation measurements were conducted on the Pd and Pd-Ag/PSS membranes at elevated temperature (623 K to 873 K) and pressures (up to 1 MPa). Surfece morphology of the deposited layer was observed with a scanning electron microscope (SEM, S3(K)0N, HITACHI Co.) equipped with an energy dispersive spectrometer (EDS, HORIBA Co.). 

The influence of Pt modihcations on the electrochemical and electrocatalytic properties of Ru(OOOl) electrodes has been investigated on structurally well-defined bimetallic PtRu surfaces. Two types of brmetalhc surfaces were considered Ru(OOOl) electrodes covered by monolayer Pt islands and monolayer PtRu/Ru(0001) surface alloys with a highly dispersed and almost random distribution of the respective surface atoms, with different Pt surface contents for both types of structures. The morphology of these surfaces differs significantly from that of brmetaUic PtRu surfaces prepared by electrochemical deposition of Pt on Ru(0001), where Pt predominantly exists in small multilayer islands. The electrochemical and electrocatal5d ic measurements, base CVs, and CO bulk oxidation under continuous electrolyte flow, led to the following conclusions ... 

The pH, EC and Fe3+ were used as control parameters. The first two were measured with an Orion probe combined pH/ATC electrode Triode and a conductivity cell DuraProbe ref. 0133030. Fe3+ was determined by molecular absorption (thiocyanate method). Mineralogical composition of the precipitates was determined by X-ray powder diffraction (XRD). Scanning electron microscopy, combined with an energy dispersive system (SEM-EDS), allowed the observation of morphological and compositional aspects of the precipitates. 

Ruthenium catalysts, supported on a commercial alumina (surface area 155 m have been prepared using two different precursors RUCI3 and Ru(acac)3 [172,173]. Ultrasound is used during the reduction step performed with hydrazine or formaldehyde at 70 °C. The ultrasonic power (30 W cm ) was chosen to minimise the destructive effects on the support (loss of morphological structure, change of phase). Palladium catalysts have been supported both on alumina and on active carbon [174,175]. Tab. 3.6 lists the dispersion data provided by hydrogen chemisorption measurements of a series of Pd catalysts supported on alumina. is the ratio between the surface atoms accessible to the chemisorbed probe gas (Hj) and the total number of catalytic atoms on the support. An increase in the dispersion value is observed in all the sonicated samples but the effect is more pronounced for low metal loading. 

The performance of a catalyst is well known to be sensitive to its preparation procedure. For this reason, ideally an oxide-supported metal catalyst should be subjected to a number of characterization procedures. These may include measurements of the metal loading within the overall catalyst (usually expressed in wt%), the degree of metal dispersion (the proportion of metal atoms in the particle surfaces), the mean value and the distribution of metal particle diameters, and qualitative assessments of morphology including the particle shapes and evidence for crystallinity. These properties in turn can depend on experimental variables used in the preparation, such as the choice and amounts of originating metal salts, prereduction, calcination or oxygen treatments, and the temperature and duration of hydrogen reduction procedures. 

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