The reaction formula of the electrode is as follows:
Negative electrode: 2H2 + 4OH- -4e-=== 4H2O
Positive electrode: O2 + 2H2O + 4e -=== 4OH -
Total reaction formula: 2H2 + O2 === 2H2O
For water to produce oxygen, electrolysis water is enough, but there are some things to pay attention to!
The so-called water electrolysis reaction is the redox reaction of water under the action of water electrical energy, in which hydrogen ions are reduced to hydrogen gas and hydroxyl ions are oxidized to oxygen.
So if you want to get only oxygen without generating hydrogen, there should be other cations that are easier to reduce than hydrogen ions. For example, for copper ions, simply add copper sulfate.
Detailed information:
On the positive electrode, the oxygen in the air and the hydrogen ions in the electrolyte absorb the electrons arriving at the positive electrode to form water. This is the reverse process of the water electrolysis reaction. Water can be reused in this process, and the principle of generating electricity is similar to solar cells that can be used at night.
The electrode materials of fuel cells are generally inert electrodes with strong catalytic activity, such as platinum electrodes, carbon electrodesactive, etc. Thanks to this principle, the fuel cell can continuously transmit energy to the outside during operation, which is why it can also be called a “generator”.
Generally speaking, writing the equation for the chemical reaction of a fuel cell requires careful attention to the acidity and alkalinity of the electrolyte. The electrode reaction that occurs on the positive and negative electrodes is not isolated, but is often closely related to the electrolyte solution.
For example, there are two types of hydrogen-oxygen fuel cells: acidic type and alkaline type. The negative electrode reaction formula in acid solution is: 2H2-4e-==4H+ and the positive electrode reaction formula. is: O2 + 4H+ +4eˉ== 2H2O; If it is in an alkaline solution, it is impossible for H+ to appear, and in an acidic solution, it is impossible for OHˉ to appear.
Baidu Encyclopedia - Réaction of hydrogen oxidation
Principle of hydrogen fuel cell: the reverse reaction of water electrolysis.
Hydrogen fuel cell is a power generation device that directly converts the chemical energy of hydrogen and oxygen into electrical energy. Its basic principle is the reverse reaction of water electrolysis, supplying hydrogen and oxygen to the anode and cathode. respectively. Hydrogen passes through the anode to the electrolyte. After the external diffusion reacts with the electrolyte, the emitted electrons pass through the external charge and reach the cathode.
Characteristics of hydrogen fuel cells
1. High efficiency
The power generation efficiency of fuel cells can reachMore than 50% is determined by the conversion properties of the fuel cell, which directly converts the chemical energy of lead into energy electrithat, without it being necessary to carry out an intermediate conversion of thermal energy and mechanical energy (generator). Dairy file
2. No noise like storm
The fuel cell operates silently, with a noise of only about 55 dB, which is equivalent to the level of a normal conversation. This makes the fuel cell suitable for indoor installation or where there are exterior noise restrictions.
3. No pollution
Fuel cells do not pollute the environment. This is by electrochemical reaction, rather than combustion (gasoline, diesel) or energy storage (battery) - the most typical traditional backup power solution. Combustion releases pollutants such as COx, NOx, SOx gases and dust. As mentioned above, fuel cells only produce water and heat. If hydrogen is produced from re energy sourcesnew products (photovoltaic panels, wind energy, etc.), the entire cycle is completely emission-free.