Hydrogen oxygen fuel cell principle question 10

No, here's how it works

If the electrolyte solution is an alkaline solution, the negative electrode reaction formula is: 2H24OH -4E ==

4h20 positive pole: O2

2h2o4eˉ==

4OH If the electrolyte solution is a salt solution, the negative electrode reaction formula is: 2H2-4E = 4H (cation), and the positive electrode: O2 + 4E + 2H2O = 4OH

During operation, fuel (hydrogen) is supplied to the negative electrode and an oxidant (air, oxygen is the component that acts) to the positive electrode. Hydrogen decomposes at the negative electrode into positive ions H+ and electrons E-. Hydrogen ions enter the electrolyte, while electrons move along the external circuit towards the positive electrode.

The load of electricity is connected to the external circuit. At the positive electrode, oxygen in the air is absorbed by hydrogen ions from the electrolyte to form water as electrons reaching the positive electrode. It is the reverse process of the electrolysis reaction of water.

Fuel cells do not rely on the difference in the chemical properties of different electrode materials to produce potential differences, but fuel cells are an energy conversion device that directly converts the chemical energy of the supplied fuel into electrical energy, and is a power generation device that can continuously obtain electricity by continuously supplying fuel. In fuel cells, the electrodes only act as directing the current and do not participate in the reaction.

The principle of hydrogen-oxygen fuel cells is galvanic cells.

The conditions that make up the galvanic cell are 1, and the activity of the electrode materials is different.

2.Forming a loop.

3.Electrolyte is present.

For fuel cells, you just need to understand that the fuel is generally used as the negative electrode, and the H2 oxygen material is used as the positive electrode.

You're talking about graphite at both poles, as if you're talking about electrolytic cells.

Generally, fuel cells are made of graphite on one side and reactive metals on the other.

What if one graphite is charged and the other is not?

Think about it, but it's up to you to think about it.

Proton exchange membrane fuel cells, also known as polymer electrolyte membrane fuel cells (PEMFC), are fuel cells mainly used in transportation, stationary fuel cells, and portable fuel cells. Its main features include a low temperature and pressure range (50 to 100 °C) and a special proton-conducting polymer electrolyte membrane.

The working principle of hydrogen-oxygen fuel cell is that hydrogen and oxygen fuel cells are batteries that use oxygen as an oxidizer and hydrogen as fuel, and then convert the generated chemical energy into electrical energy through various chemical reactions of the fuel. Hydrogen-oxygen fuel cells have many advantages, such as large capacity, high specific energy, high conversion efficiency and wide power range. Hydrogen and oxygen fuel cells are very different from general batteries, the active substances of general batteries are stored inside the battery, so the amount of active substances stored determines the capacity of the battery.

Battery narrativeA battery is a device that converts chemical energy into electrical energy in a cup, tank, or other container or composite container that contains an electrolyte solution and metal electrodes to generate an electric current. It has a positive electrode and a negative electrode. With the advancement of technology, batteries generally refer to small devices that can generate electrical energy.

Such as solar cells. The performance parameters of the battery mainly include electromotive force, capacity, specific energy and resistance.

Using the battery as energy, you can get a stable voltage, stable current, long-term stable power supply, little influence from the outside world, and the battery structure is simple, easy to carry, simple and easy to charge and discharge, not affected by the outside climate and temperature, stable and reliable performance, and plays a great role in all aspects of modern social life.

The reaction formula of the negative electrode of the hydrogen and oxygen fuel cell is: 2H2-4E-==4H+, and the positive reaction formula is: O2+4H++4E-===2H2O (acidic).

Hydrogen and oxygen fuel cells are generally made of inert metal platinum (PT) or graphite as electrode materials, with H2 at the negative electrode and O2 at the positive electrode.

Special attention should be paid to electrolytes in polar reactions.

There are three scenarios:

1. The electrolyte is KOH solution (alkaline electrolyte).

The reaction of the negative electrode is: H2 2E- 2H, 2H 2Oh 2H2O, so the electrode reaction formula of the negative electrode is: H2 2E- 2Oh 2H2O; The positive electrode is O2 to get electrons, i.e.:

O2 4E-O2, O2 can not exist alone under alkaline conditions, and can only combine with H2O to form OH, that is: O2 2H2O 4OH, therefore, the electrode reaction formula of the positive electrode is: O2 H2O 4E- 4OH.

2. The electrolyte is H2SO4 solution (acidic electrolyte).

The electrode reaction formula of the negative electrode is: h2 2e- 2h; The positive electrode is O2 to get electrons, i.e.: O2 4E- O2, O2 cannot exist alone under acidic conditions, and can only combine H to form H2O, i.e.:

O2 2HH2O, so the electrode reaction formula of the positive electrode is: O2 4H 4E- 2H2O (O2 4E- O2, O2 4H 2H2O).

3. The electrolyte is NaCl solution (neutral electrolyte).

The electrode reaction formula of the negative electrode is: h2 2e- 2h; The electrode reaction formula of the positive electrode is: O2 H2O 4E- 4Oh.

1. If the electrolyte is an acid solution

1. The negative electrode reaction formula is: 2H2-4E-==4H+.

2. The positive electrode reaction formula is: O2 + 4H+ +4E ==2H2O.

Second, if the electrolyte solution.

It is a alkali solution: 1, and the negative electrode reaction formula is: 2H2 + 4OH -4E ==4H20.

2. The positive electrode reaction formula is: O2 + 2H2O + 4E ==4OH.

Hydrogen-oxygen fuel cell property analysis:

1. The active substances (fuel and oxidizer) of the fuel cell are continuously input at the same time as the reaction, so this type of battery is actually just an energy conversion device.

2. This type of battery has the advantages of high conversion efficiency, large capacity, high specific energy, wide power range, and no need to charge, but due to the high cost, the system is more complex, and it is limited to some special purposes, such as spacecraft, submarines, military, TV transfer stations, lighthouses and buoys.

The above content reference: Encyclopedia - Hydrogen and oxygen fuel cells.

The battery is designed using the principle of electron gain and loss in redox reactions1. The product of electron gain and loss is analyzed first.

Hydrogen is exchanged for electrons to form hydrogen ions (H+), and oxygen is electrons to form oxygen anion (O2-).

2. Re-analyze whether the product can react with the substances or ions in the electrolyte, and determine the final product, which is the key to writing the electrode reaction formula.

If the electrolyte is sodium hydroxide solution, the hydrogen ions will react with hydroxide to form water, so the negative electrode reaction is H2-2E-+2OH-=2H2O

Oxygen anion will react with water to form hydroxide, that is, O2+4E-+2H2O=4OH- If the electrolyte is a dilute sulfuric acid solution, the hydrogen ion will not react again, so the negative electrode reaction is H2-2E--=2H+

Oxygen anion will react with hydrogen ions to form water, that is, O2+4E-+4H+=2H2O If the electrolyte is molten Li2O, hydrogen ions will react with oxygen anion to form water, so the negative electrode reaction is H2-2E-+O2-=H2O

The oxygen anion does not react again, i.e. O2+4E-=2O2- The reaction in the other electrolytes proceeds accordingly.

3. Finally, according to the electron conservation trim.

Solution: Hydrogen-oxygen fuel cell electrode reaction equation.

1) Alkaline medium.

Negative electrode: 2h2-4e-

4oh-=4h2o

Positive electrode: O2+4E-

2h2o=4oh-

2) Acidic medium.

Negative electrode: 2h2-4e-=4h+

Positive electrode: O2+4E-

4h+=2h2o

Methane fuel cells.

1) Alkaline medium.

Negative electrode: CH4-8E-

10oh-co32-+7h2o

Positive electrode: O2+4E-

2h2o=4oh-

Total reaction: CH4 + 2O2 + 2OH - = CO32 - +3H2O

2) Acidic medium.

Negative electrode: CH4-8E-

2h2oco2+8h+

Positive electrode: O2+4E-

4h+=2h2o

Total reaction: CH4 + 2O2 = CO2 + 2H2O

Hydrogen in oxy-fuel cells refers to hydrogen, and the preparation of hydrogen is of course varied.

1. Hydrogen production by electrolysis of water.

A series electrolyzer (similar to a filter press) with iron as the cathode surface and nickel as the anode surface is mostly used to electrolyze the aqueous solution of caustic potassium or caustic soda. The anode produces oxygen, and the cathode produces hydrogen. This method is costly, but the product purity is large, and hydrogen of the above purity can be directly produced.

This pure hydrogen is often used for: reducing agent, shielding gas and heat treatment of permalloy used in electronics, instruments and meters industry, reducing agent used in the production of tungsten, molybdenum and cemented carbide in powder metallurgy industry, preparation of semiconductor raw materials such as polysilicon and germanium, hydrogenation of grease and grease, cooling gas in dihydrogen internal coolant generators, etc. For example, the Beijing Electron Tube Factory and the Gas Plant of the Academy of Sciences use water electrolysis to produce hydrogen.

2. Water gas method to produce hydrogen.

Anthracite or coke is used as raw material to react with water vapor at high temperature to obtain water gas (C+H2O+H2-heat).After purification, it is then converted into CO2 (CO+H2O, CO2+H2) through the catalyst together with water vapor to obtain a gas with a hydrogen content of more than 80%, and then pressed into water to dissolve CO2, and then remove the residual CO in the ammonic acidic acid (or cuprous aminoacetate) solution to obtain purer hydrogen, the hydrogen production cost of this method is lower, the output is large, and the equipment is more, and this method is used more in the synthetic ammonia plant. Some also synthesize methanol from CO and H2, and in a few places, 80% hydrogen is used as a less pure gas for artificial liquid fuel.

For example, the Beijing Chemical Experimental Plant and many small nitrogen fertilizer factories in many places use this method.

3. Hydrogen production from syngas and natural gas from petroleum hot cracking.

The hydrogen production by-product of petroleum thermal cracking is very large, and it is often used for gasoline hydrogenation, hydrogen required by petrochemical and fertilizer plants, this hydrogen production method is used in many countries in the world, and in China's petrochemical bases such as in Qing Fertilizer Plant, Bohai Oilfield Petrochemical Base, etc., this square limb is used to produce hydrogen.

It is also used in some places (such as the Bay, Way and Batan Rougo hydrogen refueling plants in the United States, etc.).

4. Coke oven gas refrigeration hydrogen production.

The preliminarily purified coke oven gas is frozen and pressurized to liquefy other gases and leave hydrogen. This method is used in a few places (e.g. the Ke Mepobo factory in the former Soviet Union).

5. Hydrogen by-product of electrolysis of salt water.

In the chlor-alkali industry, there is a large amount of pure hydrogen by-products, which is surplus in addition to the synthesis of hydrochloric acid, and can also be purified to produce ordinary hydrogen or pure hydrogen. For example, the hydrogen used in the second chemical plant is a by-product of electrolysis of brine.

6. By-products of brewing industry.

When using corn to ferment acetone and butanol, there is more than 1 3 hydrogen in the exhaust gas of the fermenter, and after many times of purification, it can produce general hydrogen (more than 97%), and the general hydrogen can be further removed by cooling the silica gel tube below -100 with liquid nitrogen to further remove impurities (such as a small amount of N2) to produce pure hydrogen (above), such as Beijing distillery produces this by-product hydrogen, which is used to burn quartz products and use it for foreign units.

7. Hydrogen production by reaction of iron and water vapor.

However, the quality is poor, and the older methods of this system have been largely phased out.

Hydrogen and oxygen Xiangqian fuel cells are generally made of inert metal platinum (PT) or graphite as electrode materials, the negative electrode is passed into H2, the positive electrode is passed into O2, and the total reaction is: 2H2 O2 2H2O.

Special attention should be paid to the electrolyte in the electrode reaction, and there are three cases:

1. The electrolyte is KOH solution (alkaline electrolyte).

The reaction of the negative electrode is: H2 2E- 2H, 2H 2Oh 2H2O, so the electrode reaction formula of the negative electrode is: H2 2E- 2Oh 2H2O; The positive electrode is O2 to get electrons, i.e.:

O2 4E-O2, O2 can not exist alone under alkaline conditions, and can only combine with H2O to form OH, that is: O2 2H2O 4OH, therefore, the electrode reaction formula of the positive electrode is: O2 H2O 4E- 4OH.

2. The electrolyte is H2SO4 solution (acidic electrolyte).

The electrode reaction formula of the negative electrode is: h2 2e- 2h; The positive electrode is O2 to get electrons, i.e.: O2 4E- O2 , O2 can not exist alone under acidic conditions, and can only be combined with H to generate H2O, i.e.:

O2 2HH2O, so the electrode reaction formula of the positive electrode is: O2 4H 4E- 2H2O (O2 4E- O2, O2 4H 2H2O).

3. The electrolyte is NaCl solution (neutral electrolyte).

The electrode reaction formula of the negative electrode is: h2 2e- 2h; The electrode reaction formula of the positive electrode is: O2 H2O 4E- 4Oh.