A new catalyst that utilizes a single platinum atom could simplify hydrogen storage for renewable energy sources. The catalyst, developed by scientists at City University of Hong Kong (CityU) and tested by colleagues at Imperial College London, could be used cheaply and on a large scale.
A new catalyst using a single platinum atom, developed by City University of Hong Kong and tested at Imperial College London, promises to make it easier and more economical to store hydrogen using renewable energy sources. This innovation disperses platinum atoms on molybdenum sulfide, reducing the amount of platinum used and improving electrolysis efficiency.
Co-author Professor Anthony Kucernak, from the Department of Chemistry at Imperial College London, said: "The UK Hydrogen Strategy sets out an ambitious target of 10GW of low-carbon hydrogen production capacity by 2030. To achieve this, we need to increase production of cheap, easy-to-produce and efficient hydrogen storage. New electrocatalysts can make a significant contribution to this, ultimately helping the UK achieve its goal of net-zero emissions by 2050."
Electricity generation from renewable energy sources such as wind and solar is growing rapidly. However, some of the energy produced needs to be stored for use when weather conditions are not conducive to wind and solar energy. One promising approach is to store energy in the form of hydrogen, which can be stored and transported for later use.
To do this, renewable energy is used to split water molecules into hydrogen and oxygen, with the energy stored in the hydrogen atoms. This requires the use of a platinum catalyst to stimulate the splitting reaction of water molecules, also known as electrolysis. However, while platinum is an excellent catalyst for this reaction, it is both expensive and rare, so minimizing its use is important to reduce system costs and limit platinum extraction.
Now, in a recent study published in Nature, the team designed and tested a catalyst that uses as little platinum as possible, resulting in an efficient yet cost-effective water separation platform.
Lead researcher Professor Zhang Hua from City University of Hong Kong said: "Hydrogen produced by electrocatalytic water splitting is considered to be one of the most promising clean energy sources to replace fossil fuels in the near future and can reduce environmental pollution and the greenhouse effect."
testing tools
The team's innovation involves dispersing single-atom platinum in molybdenum sulfide (MoS2) flakes. This uses far less platinum than existing catalysts and even improves performance because the platinum interacts with the molybdenum, making the reaction more efficient.
Growing thin catalysts on nanosheet supports enabled the CityU team to create high-purity materials. Professor Kuchenak's laboratory at Imperial then characterized the materials and developed methods and models to determine how the catalyst works.
The Imperial team had the tools to carry out rigorous testing because they had developed several techniques specifically for working with this catalyst. Professor Kuchenak and his colleagues have founded several companies based on these technologies, including RFCPower, which specializes in hydrogen flow batteries.
Use hydrogen
Once the renewable energy is stored in the form of hydrogen, using it again as electricity requires conversion using fuel cells, which produce water vapor as a by-product in the oxygen splitting reaction. Recently, Professor Kuchenak and colleagues discovered a single-atom catalyst for this reaction that is based on iron rather than platinum, which will also reduce the cost of the technology.
Another spin-off company led by Professor Kuchenak, Bramble Energy, will test the technology in its fuel cells. So both single-atom catalysts - one that helps convert renewable energy into hydrogen for storage, and another that helps release that energy later as electricity - have the power to bring the hydrogen economy closer to reality.