How hydrolysis produces hydrogen

Hydrogen is gaining international attention as a potential green alternative to fossil fuels. This is because hydrogen can be “green” when produced using renewable sources. However, producing hydrogen is expensive, although large-scale hydrogen production is getting cheaper. This is due to advances in fuel cell technology – units that use hydrogen to produce electricity.

Hydrogen is also the most abundant energy source on Earth, but it is locked up in organic materials, like water and other chemical compounds. As a result, scientists worldwide are constantly looking for new ways to access this hydrogen. One such technique that scientists are currently researching is hydrolysis.

Hydrolysis: An introduction

Hydrolysis is when water is used to break down chemical substances or bonds. Two or more new substances are formed through this process. It is the opposite of condensation. Hydrolysis comes from the word hydro, Greek for “water”. Lysis is the Greek word for “unbind”.

The most common forms of hydrolysis

Scientists have developed a few different ways of performing hydrolysis. This is because of the different types of chemical reactions that are possible and whether the reaction takes place in a liquid or vapour form. There are three main types of hydrolysis: salt, acid and base.

Salt hydrolysis

This is when salt from a weak base or acid dissolves in liquid. The water spontaneously reacts with the base or acid to form different forms of hydrogen, like hydroxide ions. Simply put, a base is a chemical compound that is alkaline, like soap. An acid is the opposite, like vinegar or lemon juice.

Acid hydrolysis

In this reaction, water is combined with an acid, producing hydrogen. This type of reaction is also used to make soap.

Base hydrolysis

A base like ammonia is added to the water, ultimately producing hydrogen.

Examples of producing hydrogen through hydrolysis

Seawater

Hydrogen can be generated using hydrolysis and seawater. This process uses sodium borohydride, a white powder-like substance, and combines it with water to produce hydrogen. However, the process is slow, so scientists have found a way to speed this up by adding an acid and seawater. This chemical is called phosphotungstic acid – a chemical frequently used by scientists in both chemical and biological work.

The use of seawater instead of regular water, which is done to speed the hydrolysis process up, means that the method could be used in coastal areas.

Magnesium hydride

This chemical compound produces a lot of hydrogen when it mixes with water through hydrolysis. For this reason, scientists believe that magnesium hydride could be used to produce hydrogen on-site for the production of fuel cells. They have developed various techniques for this method, including adding salts or acids to the hydrolysis process and experimenting with temperature. Scientists have found that a related chemical compound, magnesium silicide, also has the potential to produce hydrogen through hydrolysis.

How hydrolysis is used to generate energy

The main forms of generating hydrogen for fuel or energy are steam methane-reforming and electrolysis. In steam methane-reforming, scientists use high-pressure steam and methane, usually sourced from natural gas, and a catalyst to produce hydrogen. With electrolysis, scientists use electricity to split hydrogen from water using a catalyst. While hydrolysis is not commonly used to produce hydrogen, a lot of research is being done on how it can be used.

For example, Blackstone Green Energy company is experimenting with using zinc hydrolysis to produce green hydrogen. The company claims this could be a cheaper method than electrolysis. Blackstone says that it takes zinc from its own ore deposits. This process helps the company avoid emissions that can come from producing electricity using fossil fuels and from the natural gas used to produce methane for steam-methane reforming.

Chinese scientists have also experimented with using a hydrogen fuel cell, a lithium battery and a solar panel to create a hybrid power system. The scientists produced hydrogen for the fuel cell by using hydrolysis, sodium borohydride and water.

The future of hydrolysis in South Africa

South Africa has spent a decade investing in the development of green hydrogen fuel technologies. Now, the country appears ready to turn this work into reality, with both public and private sectors planning to use hydrogen as an alternative to fossil fuels.

There are many opportunities in this industry for South Africa to exploit. For example, industry experts have talked about turning state-owned electricity producer Eskom’s decommissioned coal plants into green hydrogen chemical hubs. Furthermore, South Africa’s rich platinum resources can be used to grow the hydrogen fuel-cell industry.

Scientists from the University of Witwatersrand in Johannesburg say that the country’s abundant solar and wind resources mean that there is huge potential for green hydrogen production.

Hydrolysis is an alternative way for the country to gain access to this all-important chemical and become a world leader in green hydrogen production.