Crystallinity and morphology

Recently, rhodium and ruthenium-based carbon-supported sulfide electrocatalysts were synthesized by different established methods and evaluated as ODP cathodic catalysts in a chlorine-saturated hydrochloric acid environment with respect to both economic and industrial considerations [46]. In particular, patented E-TEK methods as well as a non-aqueous method were used to produce binary RhjcSy and Ru Sy in addition, some of the more popular Mo, Co, Rh, and Redoped RuxSy catalysts for acid electrolyte fuel cell ORR applications were also prepared. The roles of both crystallinity and morphology of the electrocatalysts were investigated. Their activity for ORR was compared to state-of-the-art Pt/C and Rh/C systems. The Rh Sy/C, CojcRuyS /C, and Ru Sy/C materials synthesized by the E-TEK methods exhibited appreciable stability and activity for ORR under these conditions. The Ru-based materials showed good depolarizing behavior. Considering that ruthenium is about seven times less expensive than rhodium, these Ru-based electrocatalysts may prove to be a viable low-cost alternative to Rh Sy systems for the ODC HCl electrolysis industry. 

VII. Effects of Crystallinity and Morphology Vin. Effects of Plasticizers and Copolymerization... 

The important factors in PLA biodegradation are the molecular weight and polydispersity, as well as the crystallinity and morphology of the polymers [36], Others factors that may affect PLA degradation include chemical and configurational structure, fabrication conditions, site of implantation, and degradation conditions. 

The properties of all but the two lowest molecular weight linear polyethylene samples have been previously described. (3/7) These include molecular weight, degree of crystallinity and morphological form. S) ( ) The fraction = 8.6 x 10 was... 

Control of the pH and temperature of the precipitating solution is important to provide optimised conditions for stoichiometric, homogeneous, fluorhydroxyapatite formation. Similar conditions and set-up can be used for the synthesis of fluoride-substituted apatite crystals with varying size, crystallinity and morphology depending on the preparation temperature [124] a purge of the synthesis system with nitrogen gas ensures the preparation of carbonate-free fluorhydroxyapatite at ambient temperature [125]. 

Highly crystalline 0-chitin is obtained from pogonophore tubes and the spines of certain diatoms, and is analogous in both crystallinity and morphology to the cellulose obtained from Valonia cell walls. Intensity data (10) were obtained for 61 observed non-meridional reflections for a specimen of dispersed (sonicated) crystallites of pogonophore tube (Oligobrachia... 

The effect of silica to alumina ratios in the alkylation of aromatics is difficult to study separately because upon changing the Si/Al ratio in the thesis gel both the ratio in the zeolite and the crystal size are changed [97], as well as the crystallinity and morphology. If the Si/Al ratio is changed in a post-treatment stq> by dealumination, vsdiich can be done either by add washing or by steaming, extra framework aluminium ecies are fr>rmed. These edes can block pores and thereby modify the diffiisivities of the reactants and products in the pores and can form a complex with remaining fr-amework aluminium t diich may result in a modified addity of the catalyst. 

Very little work has been done on nucleation rate expressions under high supersaturations, on the nature of the solids formed during rapid nucleation (which may be nonequilibrium and/or amorphous phases), or on the relative nucleation rates of polymorphs or optical isomers. Devices to achieve high supersaturations such as jet mixers or supercritical fluid precipitators must be designed properly to achieve rapid mixing and uniform crystallization conditions. Research in these areas will facilitate production of fine particles of desired crystallinity and morphology. 

Variation in the solution pH values was only slight (Table I) the values did not appear to be affected significantly by the precipitation reaction. The precipitates were amorphous and dissolved in IN HCl almost instantaneously no gibbsite or any crystalline phase of aluminum phosphate was observed with x-ray diffraction or electron microscope. No change in composition, crystallinity, and morphology was noticed during aging up to at least six months. 

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