[Chemistry Class Notes] Hydrogen Fuel Cell Pdf for Exam

Hydrogen is one of the simplest elements consisting of one electron and one proton. Moreover, it is most abundantly present in nature. However, it is not present in its gaseous form on the earth naturally. This simple element is always found combining with other elements and forms compounds like water H2O.

However, for the past few years, scientists have researched and found that hydrogen can be used as an alternative fuel – hydrogen fuel. Furthermore, its popularity is inclining drastically as this fuel is capable of producing a huge quantity of heat on combustion.

So, what is a hydrogen fuel cell? And what are hydrogen fuel cells used for? You can find all answer related to this fuel option in the following content.

What is Hydrogen Fuel?

First, you must understand what is hydrogen fuel. It is a zero-emission fuel which is produced burning of hydrogen with oxygen. Also, you might get astonished by the fact that this alternative fuel can release a greater amount of energy compared to petrol and diesel. More specifically, it is three times more efficient than petrol.

Furthermore, while burning, hydrogen fuel produces a lot of lesser pollutants than petrol or diesel. Nearly around 95% of hydrogen is formed by steam reforming of fossil fuels or by partial methane oxidation.

However, by coal gasification or water electrolysis, hydrogen can also be produced with zero carbon emission. Other than these processes, certain bacteria and algae also release hydrogen by utilising sunlight under specific conditions. Organic compounds, precisely the hydrocarbons that create several fuels like natural gas, gasoline, propane, and methanol, are also a large source of hydrogen fuel.

Hydrogen Fuel Cell

To know about hydrogen fuel cell, at first you should know what a fuel cell is.

A fuel cell is a mechanical device that can convert the energy captured within molecular bonds or chemical potential energy into electrical energy. Now, the proton exchange membrane of a hydrogen fuel cell uses hydrogen and oxygen as fuels. This PEM cell combines oxygen and hydrogen to create heat, electricity, and water.

The anode of this fuel cell carries hydrogen, and the cathode carries oxygen. Here, these hydrogen molecules divide into protons and electrons at the anode part of the cell. And due to the applications of hydrogen fuel cells, these two elements react, and these cells produce a huge amount of energy.

Thus, often, this fuel cell is compared to batteries. Both fuel cells and batteries produce energy via chemical reactions and transfer that energy into workable electric power.

Key Points

  • Hydrogen fuel carries nitrogen oxides or NO as pollutants. This is because hydrogen molecules treat nitrogen gas as one of the impurities. 

  • By adding water to the cell container, this pollution can be further reduced. This process can prevent the reaction of nitrogen and oxygen.

  • As you know, hydrogen belongs to the first place in the periodic table as it is lighter than air. So, a fuel cylinder containing hydrogen can weigh much lesser than of petrol or diesel. 

  • The temperature needs to be decreased at 20 K to keep hydrogen gas into a liquid state. However, due to the produced heat in reaction, this becomes quite difficult. Thus, it is affecting fuel efficiency. Now, scientists around the globe are researching to find out a way to use hydrogen fuel more simply.

So far, you have learnt some basic yet important information to answer what is a hydrogen fuel cell, and how does it work. 

Quiz 1.0

  1. What is the process used in a hydrogen fuel cell to generate electricity?

Options:

  1. Fusion

  2. Organic reaction

  3. Combustion

  4. Electrochemical reaction

  1. What does fuel cell emit?

Options:

  1. Carbon

  2. Water

  3. Oxygen

  4. Hydrogen

  1. How can you increase the electricity amount of a fuel cell mechanism creates?

Options:

  1. Supplying more oxygen

  2. Supplying more hydrogen

  3. Supplying more protons

  4. Supplying more cells

  1. What is the process of refuelling a fuel cell vehicle?

Options:

  1. Refuel with water

  2. Plug it into an electric charging station

  3. Pump hydrogen into the fuel tank

  4. Fill the tank with gasoline.

  1. What percentage of the known universe is composed of hydrogen?

Options:

  1. 75%

  2. 50%

  3. 99%

  4. 25%

Answers

  1. d. Electrochemical reactions. Fuel cells produce electricity via electrochemical reactions similar to a battery without combustions. However, contrary to a battery, a fuel cell does not wear out as long as there is a continuous fuel source.

  2. b. Fuel cells only emit water, heat, and energy.

  3. d. Multiple fuel cells are merged to come up with fuel cell stack to boost the amount of electricity produced. As one fuel cell can produce nearly one volt of electricity, the stack can create more.

  4. c. To refuel a fuel cell vehicle, you need to fill the tank with hydrogen directly from a fuel station.

  5. a. 75%.

Hydrogen Fuel Production

As said earlier, even though hydrogen is abundantly available in the atmosphere, it is not found in its pure form. Hydrogen composes almost 75% of all substances present in the universe. However, for an industrial scale of usage, it needs to be present as primary energy. 

Here are some conventional methods for the production of hydrogen fuel.

Process

Mechanism

Steam Reforming or Gasification

In this process, hydrocarbons or natural gases like methane react with high-temperature steam. This reaction releases a synthesis gas, a combination of hydrogen, carbon dioxide, and carbon monoxide. This carbon monoxide again reacts with water and produce extra hydrogen. 

This synthesis gas can be generated by reacting biomass or coal with oxygen and high-temperature steam inside a pressurised gasifier. This process is also called gasification. This is the most efficient, common and cheapest method to produce hydrogen fuel till now.

Electrolysis 

During this process, an electric current passes through water and splits it into oxygen and hydrogen. If the electricity can be produced through renewable sources like wind or solar, the resulted hydrogen can also be regarded as renewable. This process can have several emission benefits, and it is cost-effective as well.

Reformation of Renewable Liquid

This method uses renewable liquid fuels like ethanol and react it with high-temperature steam for hydrogen fuel cell production.

Fermentation

In fermentation, biomass is transformed into a feedstock that contains high sugar. After that, those sugar-rich feedstocks are fermented to create hydrogen.

Besides these methods, some other hydrogen production processes are in developmental or research phase. Some of these methods are the photobiological, high-temperature, and also photoelectrochemical splitting of water.

Uses of Hydrogen Fuel

The main uses of hydrogen fuel cells are an alternative power option for aeroplanes, cars, boats, etc. It can be used as a portable or stationary application of fuel cell that can power electric motors. However, it is not easy to store H2 in high pressure or cryogenic tank. And that is a primary problem of considering hydrogen fuel cell in vehicles.

Quiz 2.0

  1. Which are the most popular methods to produce hydrogen fuel?

Options:

  1. Quantum mechanics

  2. Thermal conductivity

  3. Electrolysis and steam reforming

  4. Electrolysis and absorption

  1. In which year the first-ever fuel cell was invented?

Options:

  1. 1920

  2. 1789

  3. 1894

  4. 1839

  1. What are the by-products of the fuel cell system?

Options:

  1. Water vapour and heat.

  2. Water and carbon dioxide.

  3. Water and carbon monoxide.

  4. Water and hydrogen monoxide.

  1. Which one is the major setback of the fuel cell mechanism?

Options:

  1. Pollution

  2. Weight

  3. Cost

  4. Longevity

  1. Where in a fuel cell are hydrogen ions produced?

Options:

  1. Anode

  2. Cathode

  3. The positive terminal of a battery

  4. Electrolyte centre 

Answers

  1. c. Electrolysis and steam reforming are the two most cost-effective and common processes to produce hydrogen.

  2. d. In the year 1839, Sir William Robert Grove invented first-ever fuel cell. 

  3. a. Water vapour and heat are the by-products of this fuel cell system.

  4. c. Cost is one of the significant downsides of this mechanism.

  5. a. Hydrogen ions are generated in the anode cell.

Hydrogen Economy

  • Hydrogen economy implies a vision of considering hydrogen as an alternative power generator with low-carbon emission. For example, one of the objects of this fuel cell is to replace natural gasses as heating fuels or gasoline as a fuel for transportation.

  • The elemental benefit of this system is that here hydrogen instead of electricity transmits the energy.

  • In present day, it is operated by combining with natural gasses to enhance efficiency. Moreover, in the near future, this fuel is expected to be used widely.

Hydrogen Fuel: Advantages

  • The main advantage of a hydrogen fuel cell is that it only emits water. Thus, it is eco-friendly.

  • While burning, hydrogen does not generate carbon dioxide.

  • Electrolysis and steam reforming

  • The fuel cell engines are more efficient than an internal combustion engine.

Now, you must have understood the importance of hydrogen fuel cell in human life as well as the environment. If you need any more information about what is a hydrogen fuel cell and its uses, advantages, etc., you can visit our website today. You can also download our app for easier access.

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