Hello @LatinXChem my name is Jose Ramiro Higuera and I am studying Msc. in nanotech at @TecdeMonterrey, and my interests are in carbon and metals nanostructures. Of course, my poster for #LatinXchem is of this. I open thread.
#LatinXchemNanomat #Nano078

Electrohilado de Nanofibras Poliméricas Dopadas con Nanopartículas de Hierro para Producción de Materiales Híbridos con Nanoestructuras de Carbono/Electrospinning of Polymeric Nanofibers Doped with Iron Nanoparticles for the Production of Hybrid Materials with NanoCarbon

This investigation is the begging of a larger ongoing project to generate processes for composite of carbon/metal/carbon nanostructures for the generation of supercapacitors. The idea is that by these structures the surface area and electric properties are augmented.

As such the of the structure should go up, and the literature supports this, as in it when a carbon nanostructure is dopped or adorned the capacitance increases.

In this part of the project we synthetized by pyrolysis, from an electrospun polymer fiber with an iron salt dissolved in it, carbon nanofibers with iron nanoparticles in the surface. The synthesis of the nanoparticles happens in situ at the oven.

First, we made the solution of polymer (polyacrylonitrile) and the iron salt (ferrous chloride), in DMF (dimethylformamide), as a note the quickest way to do it was to add the dry parts first, mixing and after that add the DMF.

This solution can just be used if it was done the night before or less time, because if more time passes, the solution ends up looking like this:

The next part is to electrospin this solution, we used two approaches, by a static collector (just an aluminum paper wall) and a rotatory one (made in house members of other teams). The differences of parameters are because the different voltage sources used.

Here we can see the results of the fibers without, and with ferrous chloride, it can clearly be seen that the one with the iron takes a yellow color from the salt while the one without is white.

When we see the fibers with iron salt under SEM, we see that 2 things happens, when the solution is just made and electrospun, there isn't any visible particles, if the solution was left more than one night between process some big particles appears:

We can confirm the existence of iron in the well form fibers from before using EDS, in this we can see taht around 3.5% of the mass (0.88% of atoms) was present.

Now looking at a SEM of just PAN fibers, they do not seem to have differences compared to the iron having fibers that were electrospun just after mixing.

With this we continue to pyrolyze these fibers following the following process, thanks to the microfluidics team of Tec of Monterrey for generating this process for PAN.

The Pyrolyzed PAN/iron fibers looked like this

Under SEM we can see that when pyrolyzed the fibers with iron, formed in its surface iron nanoparticles of iron/iron oxide (the oxide happens because of the interaction with the oxygen in the ambient)

To confirm that the fibers had pyrolyzed 100% FTIR was made of 2 fibers before and after pyritization, solution 1 was pure pan, and solution 2 had iron. The top 2 are before and it can be seen the expected points of a PAN FTIR, where after it disappears, showing that it is only C

Another interesting thing is that we can see with the pyrolyzed fibers with iron nanoparticles had some marked absorbance at higher wave number. This could be thanks to the metal nanoparticles, as normally metals can show in that zone of the FTIR.

And with that we reach what we have been able to do fulfilling our objectives of this part of the investigation.

We were able to, find and form PAN nanofibers incorporating iron salt, forming carbon nanofibers with iron nanoparticles.

This nanoparticles had a wide size distribution, which we are working on currently to control. Independent of that, they are in the surface, which was our objective, because they can be use as grow points for the next carbon nanostructures using CVD, in which we are working now.

So, if everything goes right next year, I will be presenting those results.
Because this thread would be really long with the references in it, I will link to a document with all the references used in this investigation: https://docs.google.com/document/d/1_3C1briZEuAunsSR7wyzNzbP28RlFQkOoCA8GsOGIYY/edit?usp=sharing

Pls any doubts feal free to ask either here or by dm however you feel comfortable.
Or anything else I am at [email protected]