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Make Your Own Glassy Carbon Electrodes

Glassy Carbon Homemade

Purpose: The purpose of this document is to provide information regarding the preparation of homemade glassy carbon electrodes. These electrodes were designed at MIT by a colleague and I to decrease the cost for electrodes that are heterogeneously functionalized. As such, this procedure enables the construction of modular RDE tips that can be functionalized and treated with chemicals in the absence of epoxy and other attachments. They work great for homogeneous experiments (CV, RDE, etc) and heterogeneous experiments once functionalized (RDE, CV, RRDE, etc).

Procedure:

1. Acquire the desired holders for these RDE slugs (The GC buttons go into the holder in the bottom left).


2. Acquire Glassy Carbon Rods:

I would recommend going with SPI but there are other vendors. The standard is 5 mm OD, but you can obviously do this with other sizes but you may need to modify some Teflon



3. Cut the Rods to desired lengths (5 mm):

If you have a machine shop, it might be useful to have them do this for you. Make sure you use a diamond blade or something compatible with carbon. Glassy carbon tends to chip, so you don’t want to go too fast. Below is how you can cut your own rods using a Dremel with a diamond blade



4. Round Edges of the Carbon Buttons:

This step is critical to ensure that the back side does not warp the Teflon insert over time. Put a nice round edge on the backside, then put a smaller edge on the front side to minimize it biting into the polishing pads.



6. Polish the Front Side:

This is arguably the most tedious part. Its helpful to have Teflon polishing holders for this. You can purchase these from pine, or make a custom one like that shown below which holds 6 at a time!! You will want to start with 1000-2000 grit sandpaper (works great when wetted with IPA) and work your way down to Diamond/Nylon (10-1 micron) then Alumina/Felt (1 to 0.05 micron). Be sure to sonicate in ethanol or IPA after each step!!



7. Marvel at your Creation:

You just saved some $ and got to use power tools.


Other Notes:

Honestly, the hardest part about this is polishing. If you don't have access to a machine shop to cut the rods "true", and you don't have access to a dremel/power tools or don't know how to use them, you could probably have a longer teflon piece machined to fit the E4 changedisc holder but be compatable with a 10 mm x 5 mm piece by SPI (basically a longer white endpiece on the first picture). You could also inquire about custom made 5 x 5 mm pieces.


If you are doing cyclic voltammetry on homogeneous solutions and want a small volume, try having a glassblower make you a 3 necked (14/20) rbf with a ~5 mL volume. Just be sure to have the necks long enough to be able to host the changedisc RDE holder.


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