Education
Hydrogen Basics
Hydrogen is the most abundant element on earth. With only one proton and one electron, it is also the simplest, lightest element. And hydrogen has the highest energy content by mass of any known fuel. Stars are made mostly of hydrogen and helium, including our sun.
Hydrogen gas (H2) is not found naturally on earth. It can, however, be extracted from other compounds. Hydrogen always combines with other elements to form new compounds like water, table sugar, ammonia, and hydrogen peroxide. Hydrogen is considered one of the building blocks of life.
Hydrogen is abundant and full of energy. But using hydrogen for energy presents some challenges.
Using Hydrogen for Energy
Hydrogen has to be extracted, or pulled, from other sources or compounds. This requires energy. For example, let's look at a water molecule, H2O. It is made up of two hydrogen atoms and one oxygen atom. The atoms share electrons to make a molecular bond. This bond is so strong that it requires electricity to break it, in a process called electrolysis. It is possible to extract hydrogen in a classroom. See this experiment. The activity uses electricity from a battery to separate the water molecule (H2O) into hydrogen (H2) and oxygen (O2).
Fuel cells use a process that is the opposite of electrolysis. Instead of breaking apart a bond, fuel cells create new bonds. This process generates electricity. Here's how: The catalyst in the fuel cell breaks apart O2 and H2 molecules. The fuel cell forces some of the electrons from the atoms to travel through an electrical circuit to generate electricity. The oxygen and hydrogen atoms re-form as water molecules (H2O).
Learn more about Hydrogen and Fuel Cells
- How do fuel cells work?
- How do we get hydrogen for fuel?
- The case for alternative fuels
- The next steps to a hydrogen economy
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