Preparing electrodes for non-aqueous PEC

It is essential that everything used in these sensitive experiments is cleaned appropriately and given enough time to dry. This cleaning process will take at least a few hours of your time, plus time overnight for everything to dry appropriately. Plan accordingly.

Caution: Many of these steps require the use of aqua regia. Undergraduates have to be trained in the use of aqua regia by graduate students or Grimm. Additionally, be sure to let everyone in the lab know that you are using aqua regia prior to use, and at least one grad student / Grimm is in the second floor lab area and aware that you are using aqua regia. Be sure to use gloves, sufficiently sized glassware, and the sodium bicarbonate buffer tray when performing cleaning with acids! Be sure to capture all aqua regia waste in a glass acid waste bottle and rinse all glassware appropriately.
Electrochemical cell glass piece:

1. Scrub out with Alconox soap (10 g/L in water). Additional Alconox is under the sink.
2. Rinse with lots of 18 MΩ water inside and out in the sink.
3. Dry off ONLY THE OUTSIDE using paper towels.
4. Set upright in a stable configuration inside a 1000mL beaker so that you can cover the cell with aqua regia.
5. Prepare aqua regia (3 vol parts hydrochloric acid, 1 part nitric acid) in another 1000mL beaker, or multiple beakers to be safe when pouring.
6. Let it turn bright orange and bubbly, then carefully pour the aqua regia over the cell until the liquid fills and covers the cell glassware. The image below is the cell, placed in a 1000mL beaker, covered in aqua regia.


7. Let the aqua regia work for a minimum of 15 minutes. The maximum time is overnight. If walking away from aqua regia, cover loosely with a glass slide / petri dish, and put a label nearby with your contact information, including a cell phone number.
8. Carefully pour out the aqua regia into an appropriate waste bottle, without harming the cell glassware piece. Rinse the beaker and cell twice with the water wash bottle.
9. Take the beaker and glassware over to the sink and rinse three times with 18 MΩ water.
10. Dry off the cell with the Argon gun, but don’t worry about getting all the water droplets out of the inside.
11. Wrap the cell in clean foil and leave in a hot oven (~100 °C) at least overnight. Don’t leave sitting upright (don’t want to scratch the bottom).
12. When ready to pump into the glovebox, transfer while hot.

Pt Electrodes:

If “regular” PEC in which we have both the reduced and the oxidized form of the redox couple (e.g. CpFe+/0, Cp’2Fe+/0, Me8Cp2Fe+/0, Cp*2Fe+/0, Cp2Co+/0, Cp*2Co+/0).  You need a Pt wire electrode and a Pt mesh electrode.  There are several with glass-platinum seals so as to be epoxy free.

1. Fill a test tube or beaker with Alconox. Submerge at least 2/3 of the way up the glass. Sonicate in Alconox ~5 minutes.
2. Rinse in 18 MΩ water.  From this point on, don’t touch the bottom 2/3s of the glass or the electrode itself.
3. Put in to a CLEAN test tube.
4. Fill up with active (read: made ~5 min in advance, and already turned yellow/orange and slightly bubbly) aqua regia.
5. Let the electrodes sit in aqua regia for 1-2 minutes MAXIMUM. This cleans the platinum without dissolving it.
6. Remove the electrodes, carefully rinse into aqua regia waste twice with water bottle.
7. Take the electrodes to the sink for copious rinsing with the 18 MΩ water.
8. Dry with the argon gun.  Dry in the direction so that water droplets move up from the Pt, up the glass and towards the unclean portion of the glass (i.e. don’t dry “dirty” water droplets from the top towards your clean Pt).
9. Set down the electrodes with the Pt suspended in the air somehow.
10. Rinse out the test tube several times in water and dry with the argon gun.
11. Put the electrodes back in the clean test tube, put the test tube in a beaker, and put the beaker in the hot oven (test tube and beaker are serving to protect Pt from contamination / getting banged around in oven).
12. When ready to pump into the glovebox, transfer while hot!

Electrodes made with your semiconductor of interest:

0. No idea. We need to figure out how to clean this material without killing it. This depends entirely on your material.

Teflon:

For your experiments, you need 3 thermometer adapters for 14/20 and one for 24/40.  And need a tiny (8-10 mm long) teflon-coated stir bar.

1. Pull apart teflon body, viton gasket, and green screw cap
2. In a CLEAN beaker sonicate all of the pieces sequentially in soap water (rinse with water afterwards), water (rinse with water afterwards), IPA (rinse with IPA afterwards). Clean out beaker in between steps as well, as this will hold the cleaned adapters when done.
3. Put into a COLD oven if we have one (temp < 100 °C) and put at the furthest point from the heat source (likely the top shelf).  If we don’t have a cold oven, it is okay to heat only the teflon bits in a hot oven. Leave the viton gaskets and green screw caps out to air-dry on a clean surface.
4. Pump in the hot teflon in hot glass and warm viton/green screw caps (you can pour the room temp viton and green screw caps into the beaker with the hot teflon when inserting in to antechamber).