We show how to make Manganese Dioxide electrodes.
Warning: Nitric acid is corrosive and nitrogen dioxide is toxic. This experiment should be performed outside or in a fume hood.
Take 1 gram of highly highly pure manganese dioxide and add 1.45g of oxalic acid dihydrate. Then add in 5 mL of water. The oxalic acid will react with the manganese dioxide to form manganese carbonate along with water and carbon dioxide. When the reaction slows down, carefully add in 1.7mL of nitric acid a few drops at a time. The nitric acid will neutralize the manganese carbonate and produce manganese nitrate and carbon dioxide. Pipette the liquid to another container, away from the excess manganese dioxide.
Evaporate the solution until it just starts to precipitate/crystallized.
To make the electrodes take a sanded titanium strip and immerse in concentrated hydrochloric acid until it bubbles evenly. Wash off the excess acid with distilled water. Apply a layer of manganese manganese solution to the titanium and then place the titanium on the hot plate set to least 300 celsius. Press down with a rod or spatula and as the electrode heats up the manganese nitrate will decompose into manganese dioxide and release nitrogen dioxide. When the electrode stops belching out brown nitrogen dioxide, immerse the electrode in water and wipe away any loosely bound manganese dioxide. Then apply another layer of manganese nitrate and repeat the process as many times as necessary.
Eventually you'll have a manganese dioxide on titanium electrode.
23 июл 2024
