A novel catalyst based on single platinum atoms could make storing renewable energy as hydrogen considerably easier in the near future.
The new catalyst, created by scientists at City University Hong Kong (CityU) and evaluated by colleagues at Imperial College London, could be inexpensively scaled up for widespread application.
The UK Hydrogen Strategy sets out an ambition to reach 10GW of low-carbon hydrogen production capacity by 2030. To facilitate that goal, we need to ramp up the production of cheap, easy-to-produce and efficient hydrogen storage. The new electrocatalyst could be a major contributor to this, ultimately helping the UK meet its net-zero goals by 2050.
Anthony Kucernak, Study Co-Author and Professor, Department of Chemistry, Imperial College London
Renewable energy generation, such as wind and solar, is quickly expanding. However, part of the energy created must be stored for use when wind and solar conditions are unfavorable. One viable approach is to preserve energy as hydrogen, which could be stored and transferred for later use.
This is accomplished by using renewable energy to split water molecules into hydrogen and oxygen, with the energy stored in the hydrogen atoms. This method employs platinum catalysts to catalyze a reaction that divides the water molecule, a process known as electrolysis.
However, while platinum is a good catalyst for this reaction, it is costly and scarce; thus, limiting its usage is critical to lowering system costs and limiting platinum extraction.
The team has now built and tested a catalyst that needs as little platinum as possible to generate an efficient yet cost-effective platform for water splitting, according to a study published in Nature.
Hydrogen generated by electrocatalytic water splitting is regarded as one of the most promising clean energies for replacing fossil fuels in the near future, reducing environmental pollution and the greenhouse effect.
Zhang Hua, Study Lead Researcher and Professor, City University Hong Kong
The team’s breakthrough includes distributing single platinum atoms in a layer of molybdenum sulfide (MoS2). This requires significantly less platinum than previous catalysts and even improves performance since the platinum interacts with the molybdenum to increase reaction efficiency.
The CityU team was able to develop high-purity materials by growing the thin catalysts on nanosheet supports. These were then described in Professor Kucernak’s group at Imperial, which has established methodologies and models for identifying how the catalyst works.
The Imperial team has the means for rigorous testing because they have created numerous technologies that utilize such catalysts. Professor Kucernak and colleagues have founded several companies based on these technologies, including RFC Power, which specializes in hydrogen flow batteries that could be enhanced by employing the new single-atom platinum catalysts.
Once renewable energy has been stored as hydrogen, it has to be transformed into electricity using fuel cells, which create water vapor as a byproduct of an oxygen-splitting reaction. Professor Kucernak and colleagues recently unveiled a single-atom catalyst for this reaction based on iron rather than platinum, which will lower the cost of this technology.
Another spinoff founded by Professor Kucernak, Bramble Energy, will put this technique to the test in their fuel cells. Both single-atom catalysts, one assisting in converting renewable energy into hydrogen storage and the other in the subsequent release of that energy as electricity, have the potential to bring a hydrogen economy closer to reality.
Shi, Z., et al. (2023) Phase-dependent growth of Pt on MoS2 for highly efficient H2 evolution. Nature. doi:10.1038/s41586-023-06339-3