Researchers at the University of Toronto for Applied Science and Engineering and Fujitsu University have developed a new way to search through the ‘chemical space’ for materials with desirable properties.
The technique has resulted in a promising new catalyst material that could help reduce the cost of producing clean hydrogen.
The discovery represents a significant step towards more sustainable methods of energy storage, including renewable but intermittent sources such as solar and wind power.
“Increasing the production of what we call green hydrogen is a priority for researchers around the world because it offers a carbon-free way to store electricity from any source,” says. Ted SargentEdward S. Rogers Sr., a professor in the Department of Electrical and Computer Engineering and senior author on a new paper published in Case,
“This work provides a proof-of-concept for a new approach to overcoming one of the major remaining challenges, which is the lack of highly active catalytic materials to speed up critical reactions.”
Today, nearly all commercial hydrogen is produced from natural gas. This process produces carbon dioxide as a by-product: if CO2 is released into the atmosphere, the product is known as ‘grey hydrogen’, but if CO2 is captured and stored, it is known as ‘blue hydrogen’. ‘ is called.
In contrast, ‘green hydrogen’ is a carbon-free method that uses a device called an electrolyzer to split water into hydrogen and oxygen gas. The hydrogen can later be burned or reacted in a fuel cell to regenerate electricity. However, the low efficiency of available electrolyzers means that most of the energy in the water-splitting stage is wasted as heat rather than being captured in hydrogen.
T Engineering PhD candidates Jehad Abed (left) and Hitartha Choubisa with an electrolyzer capable of splitting water into hydrogen and oxygen gas. Newly discovered catalyst could increase the efficiency of this reaction (Photo by Tyler Irving)
Researchers around the world are racing to find better catalyst materials that can improve this efficiency. But because each potential catalytic material can be made from many different chemical elements combined in various ways, the number of possible permutations quickly becomes overwhelming.
“One way to do this is human intuition, what materials other groups have made and trying something similar, but it’s too slow,” says the Department of Materials Science and Engineering PhD candidate. jehad abidOne of two co-lead authors on the new paper.
“Another approach is to use computer models to simulate the chemical properties of all possible materials starting from first principles. But in this case, the calculations get really complicated, and the computational power required to run the model becomes too much.”
To find a way, the team turned to the emerging field of quantum-inspired computing. They used a digital annealer, a device that was created as a result of a long-standing collaboration between U of T Engineering and Fujitsu Research. This collaboration has also resulted in the creation of the Fujitsu Co-Manufacturing Research Laboratory at the University of Toronto.
“The digital annealer is a hybrid of unique hardware and software designed to be highly efficient at solving combinatorial optimization problems,” says hidetoshi matsumuraFujitsu Consulting (Canada) Inc. Senior Researcher in
“These problems include finding the most efficient route between multiple locations in a transportation network, or choosing a set of stocks to build a balanced portfolio. Searching through different combinations of chemical elements to find a catalyst with the desired properties is another Example, and it was the perfect challenge for our digital annealer to address.
In the paper, the researchers used a technique called cluster expansion to analyze a truly vast number of possible catalyst material designs – they estimate the total number to be on the order of hundreds of quadrillion. For perspective, a quadrillion is roughly the number of seconds that will pass in 32 million years.
The results point to a promising family of materials composed of ruthenium, chromium, manganese, antimony and oxygen, not previously explored by other research groups.
The team synthesized several of these compounds and found that the best of them exhibited a mass activity – a measure of the number of reactions that can be catalysed per mass of catalyst – compared to the best catalysts currently available. was almost eight times higher. ,
The new catalyst has other advantages, too: It works well in acidic conditions, which are a requirement for state-of-the-art electrolyzer designs. Currently, these electrolyzers rely largely on catalysts made from iridium, a rare element that is expensive to obtain. In comparison, ruthenium, the main component of the new catalyst, is more abundant and has a lower market value.
There is more work ahead for the team: for example, they aim to further optimize the stability of the new catalyst before it can be tested in an electrolyzer. Nevertheless, the latest work serves as a demonstration of the effectiveness of the new approach to chemical location finding.
“I think the exciting thing about this project is that it shows how you can solve really complex and important problems by combining expertise from different fields,” says the electrical and computer engineering PhD candidate Hitartha ChaubisaOther co-lead authors of the paper.
“For a long time, materials scientists have been looking for these more efficient catalysts, and computational scientists have been designing more efficient algorithms, but the two efforts have been disconnected. When we brought them together, we could very quickly We were able to find promising solutions. I think there are many more useful discoveries like this to be made.”