Produce green hydrogen ten times cheaper

2023-07-07 01:41:59

Researchers from the Higher Council for Scientific Research (CSIC) have participated in an international study, published in the journal Advanced Energy Materials (1), which has achieved a compound capable of generating green hydrogen using ten times less iridium, an “ultra-scarce and very expensive” transition metal, according to the CSIC.

Green hydrogen is that obtained by electrolysis of water using renewable energy

Green hydrogen is that obtained by electrolysis of water using renewable energy. In this sense, it has indicated that it is expected to “facilitate” the transition to a decarbonized society.

Efficient, but very expensive

Specifically, to obtain this hydrogen, electrolysers are needed, such as the so-called ‘PEM’ (Proton Exchange Membrane) electrolysers, which “work very well, are efficient, but are very expensive for the materials they use”, as he explained. the CSIC researcher at the Institute of Catalysis and Petrochemistry (ICP) and one of the authors of the study, Sergio Rojas.

Iridium is not only expensive, but it is one of the scarcest and most widely distributed materials.

Also, the CSIC that one of those materials is iridium “which is not only expensive, but is one of the scarcest and worst distributed materials.”

In this sense, the CSIC has informed that, currently, a troy ounce (a unit of measurement used in precious metals that is equivalent to 32.15 grams) costs $4,600according to the company Johnson Matthey.

For this reason, the researchers have designed a metallic oxide, a compound (catalyst) with ten times less iridium compared to that used commercially (from two milligrams per square centimeter to 0.2) and have achieved the same performance.

Reduced Catalyst cost by ten

“We have reduced the cost of the catalyst tenfold,” said the CSIC researcher at the Institute of Materials Science in Madrid (ICMM) and also author of the paper, José Antonio Alonso.

Likewise, he stressed that this study “demonstrates the importance of fundamental research as a step prior to applied research”. “We obtained this compound ten years ago, but until now we had not found an application for it,” he clarified.

For her part, the scientist at the ICP and also author of the study, María Retuerto, added that this study “opens the door to other similar and scalable materials”.

In addition, he explained that the scalability of this specific compound is “complex” because it requires a furnace with 200 bars of oxygen pressure, “a rare machine located at the ICMM and used by Alonso.”

“These iridium materials start from a starting compound whose surface is modified in the reaction; what we are seeing now is that maybe we don’t need to have exactly that starting compound. We can have something very similar and in the end the restructuring of the surface gives us an equal catalytic activity”, stated Retuerto.

Capable of producing large amounts of high purity hydrogen

On the other hand, Rojas has explained that scaling is producing several tons, that is, producing “massively.” Even so, he has described this compound as “a precursor to a catalyst” thanks to which other compounds are being achieved.

Likewise, the CSIC has clarified that the process by which this compound and its derivatives work have been explained by the same teams in another article, published in Nature Communications at the end of 2022, where they already defended that it was possible to lower the Iridium level of the catalysts used in ‘PEM’ electrolysis.

“Despite the fact that alkaline electrolysis is the most developed technique, PEM technology is very fast and is capable of producing large amounts of high purity hydrogen. At the moment it requires iridium in its anode and that is the big problem to introduce the technology to larger scale in the market”, Retuerto pointed out.

References (1) High Performance and Durable Anode with 10-Fold Reduction of Iridium Loading for Proton Exchange Membrane Water Electrolysis. Advanced Energy Materials. (2) Highly active and stable OER electrocatalysts derived from Sr2MIrO6 for proton exchange membrane water electrolyzers. Nature Communications.