Does anybody know what is the effect of solvent/water in MoS2/RGO nucleation and growth (particle size)? I synthesized MoS2/RGO using supercritical ethanol or water solvents system by mixing Mo(acac)2, solvents, Na2S, and GO. However, I found a problem that when I used ethanol/water mixture, the synthesized composite has a bigger crystallite size (from XRD/TEM) than that synthesized from ethanol. At first, I guess that the higher presence of water can facilitate ion mobility, thus growth is preferred to nucleation. However, in contrast, I found that my precursor (Mo(acac)2) has a better solubility and dispersion in organic solvent rather than water which may facilitate nucleation rather than growth. Can anyone help with this problem? What is actually the factor affected heterogeneous nucleation and growth? And what is the relation with water content and dispersion towards particle size?
In my case I am making magnetite nanoparticles. I also use ethanol and water. If concentration of ultrapure water increases then size of nanoparticles decreases. At lower water concentration size decreases. You can try this increase or decrease of water concentration. Please let me know your thinking about my opinion!!
I'm sorry I don't understand with your result because it seems that your second sentence and third sentence are opposites. So which one is your results? In my case when water content increases, particle size increases. Do you know what is the reason behind it? I tried to figure it out by connecting heterogeneous nucleation or growth with solubility and dielectric constant.
http://onlinelibrary.wiley.com/doi/10.1002/ejic.200900199/abstract
actually I use ethanol water mixrure.. In my case size of nanoparticles is inversly proportional. may I know what is the role of water in your experiment? is it source of oxygen in your reaction?? I think dielectric constant will be important factor. If in your case size increasing with increase in water concentration that means may be ::: Less nucleation sites are formed, less number of nuclei formed.
In my case I use mixture of ethanol and water. But I keep amount of water less than ethanol amount. I do not exceed water concentration than the ethanol concentration. And as I increase water concentration like 12M size of nanoparticles is 15nm and at 1.2M water concentration its more than 25nm. You can see my paper here is the link:
A. G. Nene, M. Takahashi, K. Wakita, M. Umeno, "Size Controlled Synthesis of Fe3O4 Nanoparticles by Ascorbic Acid Mediated Reduction of Fe(acac)3 without Using Capping Agent", Journal of Nano Research, Vol. 40, pp. 8-19, 2016
G. Nene, A. , Takahashi, M. and R. Somani, P. (2016) Fe3O4 and Fe Nanoparticles by Chemical Reduction of Fe(acac)3 by Ascorbic Acid: Role of Water. World Journal of Nano Science and Engineering, 6, 20-28. doi: 10.4236/wjnse.2016.61002.
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