The research team with Hyun Teak-hwan (Chair-professor at Seoul National University, Department of Chemical and Biological Engineering) and Sung Yeong-eun (Professor at Seoul National University, Department of Chemical and Biological Engineering), who are the leader and vice leader of Nanoparticle Research Group of Institute for Basic Science respectively, collaborated with a team of Yoo Jong-seok professor at University of Seoul to develop an electrocatalyst that can produce hydrogen peroxide eco-friendly using only oxygen and water.
As a result, hydrogen peroxide can be produced with a catalyst that is more than 2000 times cheaper than the existing noble metal catalyst, so it is evaluated as a ‘killing three birds with one stone’ technology that solves all of the cost, efficiency and environmental issues.
|▲ Leader Hyun Teak-hwan (left) and Vice Leader Sung Yeong-eun (right) attended to present the major achievements.
Hydrogen peroxide is widely used in household goods such as toothpaste and dish detergent, as well as in medical sites that require sterilization and in semiconductor processes that wastewater treatment and removal of impurities. Industrial hydrogen peroxide is mainly produced by the anthraquinone process. However, the anthraquinone process* uses expensive palladium catalysts, which not only consumes a lot of energy, but also has the limitation that organic substances are generated as by-products and cause environmental pollution.
Therefore, as the demand for hydrogen peroxide increases with the development of ultra-precision semiconductors and mechanical parts, there is a need for a sustainable process that can produce hydrogen peroxide with cheap and high efficiency.
* Anthraquinone process: A process of producing hydrogen peroxide by sequentially reducing and oxidizing anthraquinone dissolved in an organic solvent in the presence of a catalyst. Expensive palladium catalysts are required in large quantities, and excessive energy is consumed in each step, resulting in low energy efficiency. In addition, since organic solvents are generated as by-products, there is a limit that causes environmental pollution.
|▲ Control of catalytic activity through structure control around cobalt atoms (Image provided by IBS)
The research team devised an inexpensive catalyst that could electrically produce hydrogen peroxide using water (H2O) and oxygen (O2) without the need for complex steps. The catalyst, developed by the researchers, is in the form of putting a cobalt (Co) atom on two-dimensional graphene. Unlike conventional catalysts, they are inexpensive as they use cheaper cobalt atoms instead of precious metals such as platinum and palladium.
When the developed cobalt atom/graphene catalyst is added to an aqueous solution of saturated oxygen and subjected to electricity, hydrogen peroxide can be produced without adding any other compound. This catalyst has produced up to eight times higher productivity than the expensive noble metal catalysts known to be the most efficient. With 1kg of catalyst, it is capable of producing 341.2 kg of hydrogen peroxide per day. In addition, it was confirmed that even after the experiment for continuously producing hydrogen peroxide for more than 110 hours, it maintains more than 98% of the initial performance.
“The idea is based on the finding that an inexpensive atom such as iron, cobalt, or nickel effectively mediates electrochemical reactions when stabilized on graphene. It was confirmed that the activity of the catalyst could be controlled at the atomic level and even justified by calculation chemistry. Consequently, by changing the structure around the cobalt atoms, the team was able to develop a catalyst with world-class hydrogen peroxide production ability.” Said Sung Yeong-eun vice leader.
|▲ Performance Comparison of Catalysts Developed by Researchers and Conventional Catalysts (Image provided by IBS)
The catalyst developed by the researchers is a heterogeneous catalyst**, which is cheaper than a homogeneous catalyst and is eco-friendly because it does not generate waste catalyst and it can be recycled after the reaction. This work means a lot academically in the way of the world's first discovery of a principle for increasing the activity of heterogeneous catalysts at the atomic level. The researchers expect the catalyst to be used in a wide variety of chemical processes as it can synthesize products stably and environmentally at both room temperature and atmospheric pressure.
**Heterogeneous catalyst: When a catalyst has the same form with the reactants and products, it is called a homogeneous catalyst. In this time, the reaction proceeds in the form of all catalyst, reactants and products dissolved in solvent. On the other hand, heterogeneous catalysts have the advantage that they can be recovered and recycled after the reaction as the reactants and products differ from each other in the gaseous or liquid state.
“Hydrogen peroxide, the world's top 100 industrial chemicals, can now be produced environmentally and economically. It is expected to improve productivity by applying hydrogen peroxide production as well as many chemical reactions using catalysts.” Said Hyun Teak-hwan leader.
Meanwhile, the results of the research were published in Nature Materials (IF 39.124), the world's leading journal in materials, on the January 14 in Korean time.