When I was in my first year of college around 2000, the preparation of oxygen was mentioned in chemistry. I thought water electrolysis would involve hydrogen and oxygen, so I tried it myself. I myself experimented with water electrolysis and also discovered some electrodes. The knowledge of the reaction was that the voltages used at that time were DC6V (DC means direct current) and DC280V.
Note:
Use DC voltage;
It is dangerous if it exceeds 60V. Please take precautions, including but not limited to limit: insulated gloves, goggles, earplugs, arc-rated visor, arc-protective clothing, arc-rated gloves;
The power supply must have a fuse and a trip switch;
Use relatively clean water. is recommended;
A graphite electrode is recommended (use a rodof carbon positive for dry battery, just keep it clean)
Schematic diagram
Process
I made a wide mouth bottle and I filled with half a bottle of tap water. I started using 6V and directly stripped 1 cm of copper wires to use as electrodes. As a result, there were almost no bubbles in the positive electrode, and the hydrogen bubbles in the negative electrode were also very small (the diameter of the bubbles was estimated to be less than 0.2 mm). You can't even call it bubbles, just a very small foam soon (within half an hour) water; turned blue, the copper wire of the positive electrode was broken, and sediment appeared at the bottom of the bottle. Boil the water with the sediment and the substance turned black and turned out to be copper oxide, indicating that the precipitate was inside. the bottom of the bottle was hydroxyof copper. Then I tried using aluminum wire as an electrode, and it turned out to be aluminum hydroxide. I also tried the same thing with iron, and it turned out to be green flakes first, then reddish brown flakes. Finally, I used a battery core and a carbon rod. There are now bubbles and oxygen in the positive electrode. Because the bubbles were too small and too few, I adjusted the voltage, which could only be adjusted up to 9V. The bubbles increased but were not obvious. So I made a bridge rectifier filter circuit using 4 diodes and a 400 V 10 uF capacitor. The actual voltage measured by the multimeter was around 280V DC (don't short circuit it or touch it with your hands!!) After carefully switching on the positive. and negative carbon rods. The bubbles appear a lot and very quickly, likewhen the water boils. The effect is very good and achieves the effect I want. After observing for a few minutes, turn off the power and pack your things. As a child from a rural area, I didn't know who to share my joy and doubts with at that time. Later, I told my father, who had studied in high school, that he could not clearly explain some phenomena and principles. . Later, I saw a "Textbook of Formulas and Theorems for Middle School Students", which briefly mentioned the electrolysis reaction in chemistry, which partly clarified the confusion. At that time, I used DC6V to electrolyze salt water. The smell of chlorine (be careful, chlorine is harmful to the human body) will never be forgotten for long. The bottle was filled with light green chlorine.
Summary
The recommended voltage is 24 or 48 V (the voltage is too low to see obvious bubbles) and the current is about 1 A. Pure water hashigh resistance and the current is very low when it is boiling. In fact, the same reaction occurs when dry batteries are thrown into water, but the bubbles are too small to see.
The battery must be disposed of correctly and cannot be thrown into drinking water or the ground, otherwise harmful substances will enter the ground or drinking water and harm children.Sun.