Cubes Outperform Spheres as Catalyst Particles Cubes outperform Spheres as Catalyst Particles

Cubes Outperform Spheres as Catalyst Particles Cubes outperform Spheres as Catalyst Particles ...

Electrocatalysts are substances that accelerate chemical reactions in electrochemical cells. They are important components in many energy conversion and storage techniques, such as fuel cells, batteries, and electrolyzers, because they increase their efficiency and stability.

The reduction of CO2 emissions is critical in the fight against climate change. Currently, grey hydrogen, produced from oil and natural gas, is widely used, but efforts are underway to substitute it with green hydrogen, produced from renewable sources. Green hydrogen is produced through electrolysis, a process where electricity splits water into hydrogen and oxygen.

The water-splitting process is only a temporary improvement, and there are not enough powerful, long-term, and cost-effective catalysts for it.

Kristina Tschulik of the University of California at Berkeley says she is working to develop new, highly active electrocatalysts that are free of precious metals.

Her research group focuses on base metal oxide nanoparticles that are a million times smaller than a human hair. They are made on an industrial scale and vary in shape, size, and chemical composition.

Kristina Tschulik (left) and Hatem Amin are investigating nanoparticles as green hydrogen catalysts. Credit: Marquard

Kristina Tschulik of the University of Maryland describes her research on so-called catalyst inks, in which billions of particles are mixed with binders and additives. This method allows researchers to only measure an average performance, but not the individual particles' activity, which is what really matters.

"We might be able to precisely produce particles with that exact shape if we knew which particle shape or crystal facet — the surfaces that point outwards — is most active," says Dr. Hatem Amin, a postdoctoral researcher in analytical chemistry at Ruhr University Bochum.

"Our findings suggest that cobalt oxide particles in the form of individual cubes are more active than spheres, as the latter always have several other, less active features."

As part of the Collaborative Research Centre/Transregio 247, the Bochum group's experimental findings were confirmed by Professor Rossitza Pentcheva from the University of Duisburg-Essen.

"Our investigations into the interaction between particle shape and activity provide the basis for informed decision-making about viable catalyst materials," says Kristina Tschulik.

Zhibin Liu, Hatem M. A. Amin, Manuel Corva, Rossitza Pentcheva, and Kristina Tschulik, 3 January 2023, Advanced Functional Materials. DOI: 10.1002/adfm.202370006

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