[2020-03-04] Electrolytic formation and decay of KFeO2 at 20x speed

In rather crude experimentation I accidentally found that it is possible to produce the active phase of industrial potassium-iron oxide catalysts effortlessly by making relatively thin layers of molten KOH and Fe2O3 react electrolytically at about 350 °C in a standard atmosphere. Identification was performed visually from the appearance of an olive green color upon formation, and from its decay to a red-brown moist substance within minutes of ambient air exposure, both characteristics typically reported in the catalyst literature for this material.

Today I replicated the same procedure initially used when I accidentally formed the KFeO2 material. Here follows a description and comment of what is performed in this specific video:

* A thin and flat carbon steel cathode (mostly Fe) and a steel screwdriver anode are provided. A low-power DC boost converter powers them at relaively high voltages.
* I put a small flake of KOH (potassium hydroxide) on the flat cathode.
* I start heating with an atmospheric glow plasma at about 780V (current-limited with a ballast resistor in series with the circuit) the edges of the thin steel cathode.
* After a few seconds some heated portions of steel cathode change into a dark blue-gray appearance and the KOH flake starts melting. The color change of steel is due to the formation of surface oxides and should be consistent with a temperature range of about 350–400 °C, within which KOH melts.
* After most of the KOH flake melted I proceed to touch it with the anode. High voltage electrolysis occurs as a result. Occasionally tiny explosions can be heard.
* The low-power high-voltage DC power supply used will try to limit current to remain within its power budget. During electrolysis voltage decreases to 550V.
* After several seconds of continued electrolysis a bright olive green material within the KOH liquid starts appearing. This should be KFeO2, formed from Fe oxides and potassium ions.
* I occasionally try to keep the KOH molten by applying a glow plasma again to the edges of the thin cathode or directly to the KOH mixture. After this I start electrolysis again.
* After a few minutes a sizable portion of the cathode is covered by a green material in suspension within molten KOH. At this point I stop the treatment.
* The green material is not stable in air once cooled. Within a few minutes of time it reverts to a red-brown material. This behavior is also documented in the catalyst literature. It occurs due to the rapid absorption of moisture from the environment.
* On the short term this material can be reverted back to its green state if it's allowed to dry at elevated temperatures. After waiting several hours, this apparently becomes more difficult.

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