The overall goal of this procedure, is to demonstrate the Molten Salt Method as a suitable technique to synthesize high quality monodisperse Lanthium Hafnium Nanoparticles. The Molten Salt Synthesis actually has been widely used to enrich the yeast to make nanoparticles. The nanoparticles that have been made include metal oxides, flourides, and it even has been used to make intermetallic nanoparticles.
First, begin by measuring 200 milliliter of distilled water in a 500 milliliter beaker, and let it stir at 300 revolutions per minute. Measure 2.165 grams of lanthanum nitrate hexahydrate and 2.0476 grams of hafnium dichloride octahydrate. Next add all materials while stirring and allow the starting material to dissolve simultaneously.
Prepare different concentrations of the ammonia solution. For example, add 20 milliliter of ammonia hydroxide 30%to 180 milliliters of distilled water in a separate beaker to make a concentration of 3%Add the diluted ammonia hydroxide solution prepared in the previous step into the burette. In this case, we are showing the addition of 3%ammonia hydroxide concentration.
Ensure that the burette is covered at all times since the ammonia solution tends to evaporate which decreases its concentration. Start the titration in dropwise matter. Adjust the speed of the drops accordingly for a period of two hours.
After several milliliters delivered, the solution will become cloudy. This is a simple sign that the precipitate is forming. After two hours, remove the string bar and allow the precipitate to sit overnight.
Check the pH of the solution before washing. Wash the precipitate with distilled water until the supernatant reaches a neutral pH, which will normally take five to eight washes. Start a vacuum filtration setup and filter the solution by pouring it, once it has been neutralized, using a filter funnel with a filter paper.
Ensure that all complex precursor remnants are washed from the walls of the beaker. Dry the resultant precursor at room temperature. Measure 3.033 grams of potassium nitrate and 2.549 grams of sodium nitrate.
Combine the measured salts with 35 grams of the as prepared source complex precursor. One to five milliliters of acetone or ethanol can be added to the mixture to facilitate the grinding. Ensure that all solvent is evaporated before placing the mixture into the crucible.
Grind the mixed salts and precursor as fine as possible for about 30 minutes. Place the resulting mixture in a crowned-in crucible and place it in a muffle furnace. Set the furnace at 650 degrees for six hours with a ram rate of ten degrees per minute.
Is that the reaction is controlled by distress of molten salt, you can use alkali metal halide, alkali metal hydrides, and alkali metal sulfides, but that the goal reaction is governed by the way how we have chosen your molten salt. One should be sure that it have a low melting point, enough to process the reaction, and it should have it for optimum aqua solidity so that it can really move easily just by washing it with the water. Here, what these reactions do, it really reduces the formers in temperature in comparison to other high temperature route, and also it enhances the rate of reaction.
It enhances the rate of reaction by two ways. It increases the contacting of the reactant, and it increases the mobility of the reactants basis on the surface of molten salt. And here, the particles have formed a collectively low temperature at two different steps.
The one step is called reaction, and the other step is called particle growth. In reaction step, the reactant's molecules react, and they keep on reacting unless all of them are in the reaction state. Once all the reactants are consumed, the particles formation takes place on the surface of molten salt, and the growth of the particle is going to be matter.
The beauty is that all those particles which are below the science of asserting critical limit get dissolved in the molten salt, so you get the very mono dispersed particle with a very fine morphology. X-ray diffraction patterns allow for the determination of the level of purity of the synthesized nanoparticles. Representative results show that no impurities are present in the samples, since only reflective plains from the defect fluoride are being stated.
However, one main disadvantage of XRD is that it fails to distinguish between fluoride and pyrochlore structure phase. Due to its close resemblance, XRD fails to show supernatants reflection of pyrochlore structure. Therefore, another more structural sensitive technique, such as Raman spectroscopy, is needed.
Average particle size can be calculated using the pie shares equation. This equation gives fair results for spherical nanoparticles. The calculated size follows a proportional relation with the ammonium hydroxide concentration.
Raman spectroscopy has shown six vibrational modes corresponding to ordered pyrochlore phase. In general, the molten salt synthesis is an easy methodology to learn. I, as a student, find it to be an efficient process to make high quality nanoparticles.
One of the many advantages of this process is safety. The process itself does not produce any toxic fumes, and we're able to perform it in open air. In addition, there's no by-product expected to be found, which makes it a very environmentally friendly method.
To add to that, actually we have explored many applications of the molten salt synthesis to produce size two noble nanoparticles. We have optimized in this parameter, such as pH, processing time, and thermal conditions, and surely one is able to optimize these type of parameters will surely get a high quality product. And as a group, we also tried to extend the molten salt synthesis to obtain other technologically important oxides, such as among many other, and the effort to make these nano materials with well defined size, shape, and surface can be used in various catalyst, magnetic, optical, and some later applications.
