Scientists at the Argonne National Laboratory may have found a better, more efficient, and cheaper solution for producing hydrogen without consuming fossil fuels.

Although one could argue that it is not very efficient as a fuel for passenger cars, hydrogen may still play a vital role towards a clean energy future in other fields like energy storage or as a compatible replacement in natural gas infrastructures in countries like the Netherlands. (It may also be useful in heavy vehicles like semi-trucks, although that may depend on the viability of electric vehicles such as the well-known Tesla semi). One of the main issues with hydrogen production is that it has to be obtained from other substances like methane or water.

In some cases hydrogen can be a very useful for storing energy - Image Credit: Petmal via iStock/Getty Images - HDR tune by Universal-Sci

Hydrogen is the most plentiful element in the known universe. On earth, most of it is bound to oxygen in the form of water molecules or H2O. Hydrogen atoms in the shape of molecular hydrogen have to be separated from this combination in order to get usable hydrogen.

The method of removing hydrogen from H2O is dependent on a slow procedure known as oxygen evolution reaction. Oxygen evolution reaction (often abbreviated as OER) is what frees up molecular oxygen from water. Managing this reaction is essential not only to the manufacturing of hydrogen but also to an assortment of other chemical processes, among which those found in batteries.

Researchers at the Argonne National Laboratory have discovered a shape-shifting characteristic in perovskite oxides (a class of functional materials that exhibit a range of stoichiometries and crystal structures) that may be able to speed up the aforementioned Oxygen evolution reactions. They published their findings in the Journal of the American Chemical Society, providing helpful insights to assist in developing new materials for more efficient production of renewable fuels and storing energy.

An artist impression of hydrogen molecules (H2) - Image Credit: peterschreiber.media via iStock/Getty Images - HDR tune by Universal-Sci

One of the reasons why the research team looked at perovskite oxides to begin with has to do with the fact that they are far less expensive than valuable metals such as ruthenium and iridium that are currently used to do the same thing. Where prior investigations into these materials concentrated on the bulk characteristics of perovskite materials and how those relate to the OER activity, the Argonne scientists looked at the surface where the materials react with their surroundings.

Akin to a split avocado that swiftly becomes brown where it encounters the air while remaining green on the inside, the surface of perovskite materials becomes distinct from their bulk when it meets surrounding elements. The scientists postulated that this could have a significant impact on how we comprehend their characteristics.

In water electrolyzer systems, which split water into hydrogen and oxygen, perovskite oxides interact with an electrolyte made of water and particular salt species, producing an interface that enables the device to function. As electrical current is applied, that interface is essential in kicking off the process that separates oxygen and hydrogen.

Pietro Papa Lopes, lead scientists of the study, explained in a press release that once it's in an electrochemical system, the perovskite surface evolves and turns into a thin, amorphous film. It appears that it is never exactly the same as the material you begin with.

The extraordinary interactions between perovskite oxide, bringing us closer to more efficient and more affordable green hydrogen production. - Image Credit: Argonne National Laboratory

The research team joined experiments with theoretical calculations to establish how the surface of a perovskite material develops throughout an oxygen evolution reaction and discovered that the perovskite oxide's surface evolved into a cobalt-rich amorphous film, just several nanometers thick. When iron was present in the electrolyte, the iron helped speed up the OER.

The results suggest new possible approaches for composing perovskite materials. According to Lopes, understanding the dynamics of materials and their effect on the surface processes is how we can make energy conversion and storage systems better, more efficient, and affordable.

We have high hopes for this innovative approach to hydrogen production and will keep an eye on future developments. In the meantime, if you are interested in a more detailed overview of the study covered in this article, be sure to read the study published in the Journal of the American Chemical Society, listed below.

Further reading: