Infograph that explains the idea of a PEM water electrolyzer, the way it works, the brand new method applied by the group and the outcomes they obtained. Credit score: ICFO
Hydrogen is a promising chemical and power vector to decarbonize our society. Not like typical fuels, hydrogen utilization as a gasoline doesn’t generate carbon dioxide in return. Sadly, at present, many of the hydrogen that’s produced in our society comes from methane, a fossil gasoline. It does so in a course of (methane reforming) that results in substantial carbon dioxide emissions. Subsequently, the manufacturing of inexperienced hydrogen requires scalable alternate options to this course of.
Water electrolysis provides a path to generate inexperienced hydrogen which might be powered by renewables and clear electrical energy. This course of wants cathode and anode catalysts to speed up the in any other case inefficient reactions of water splitting and recombination into hydrogen and oxygen, respectively. From its early discovery within the late 18th century, water electrolysis has matured into totally different applied sciences. One of the vital promising implementations of water electrolysis is the proton-exchange-membrane (PEM), which might produce inexperienced hydrogen combining excessive charges and excessive power effectivity.
Up to now, water electrolysis—and particularly PEM—has required catalysts based mostly on scarce, uncommon components, resembling platinum and iridium, amongst others. Just a few compounds mix the required exercise and stability within the harsh chemical surroundings imposed by this response. That is particularly difficult within the case of anode catalysts, which should function in extremely corrosive acidic environments—situations the place solely iridium oxides have proven secure operation on the required industrial situations. However iridium is likely one of the scarcest components on Earth.
Within the seek for doable options, a group of scientists has not too long ago taken an vital step to seek out alternate options to iridium catalysts. This multidisciplinary group has managed to develop a novel strategy to confer exercise and stability to an iridium-free catalyst by harnessing up to now unexplored properties of water. The brand new catalyst achieves—for the primary time—stability in PEM water electrolysis at industrial situations with out using iridium.
This breakthrough, printed in Science, has been carried out by ICFO researchers Ranit Ram, Dr. Lu Xia, Dr. Anku Guha, Dr. Viktoria Golovanova, Dr. Marinos Dimitropoulos, Aparna M. Das and Adrián Pinilla-Sánchez, and led by Professor at ICFO Dr. F. Pelayo GarcÃa de Arquer; and contains vital collaborations from the Institute of Chemical Analysis of Catalonia (ICIQ), The Catalan Institute of Science and Know-how (ICN2), French Nationwide Heart for Scientific Analysis (CNRS), Diamond Mild Supply, and the Institute of Superior Supplies (INAM).
Coping with the acidity
Combining exercise and stability in a extremely acidic surroundings is difficult. Metals from the catalyst are inclined to dissolve, as most supplies should not thermodynamically secure at low pH and utilized potential in a water surroundings. Iridium oxides mix exercise and stability in these harsh situations, and that’s the reason they’re the prevalent alternative for anodes in proton-exchange water electrolysis.
The seek for alternate options to iridium is just not solely an vital utilized problem, however a basic one. Intense analysis within the seek for non-iridium catalysts has led to new insights into the response mechanisms and degradation, particularly with using probes that would examine the catalysts throughout operation mixed with computational fashions. These led to promising outcomes utilizing manganese and cobalt oxide-based supplies, and exploiting totally different constructions, composition, and dopants, to switch the physicochemical properties of the catalysts.
Whereas insightful, most of those research had been carried out in basic not-scalable reactors and working at softer situations which might be removed from the ultimate utility, particularly by way of present density. Up to now, demonstrating exercise and stability with non-iridium catalysts in PEM reactors and at PEM-relevant working situations (excessive present density) had remained elusive.
To beat this, the ICFO, ICIQ, ICN2, CNRS, Diamond Mild Supply and INAM researchers got here up with a brand new strategy within the design of non-iridium catalysts, attaining exercise and stability in acid media. Their technique, based mostly on cobalt (very ample and low cost), was fairly totally different from the standard paths.
“Typical catalyst design usually focuses on altering the composition or the construction of the employed supplies. Right here, we took a distinct strategy. We designed a brand new materials that actively entails the elements of the response (water and its fragments) in its construction. We discovered that the incorporation of water and water fragments into the catalyst construction might be tailor-made to defend the catalyst in these difficult situations, thus enabling secure operation on the excessive present densities which might be related for industrial functions,” explains Professor at ICFO GarcÃa de Arquer.
With their method, consisting of a delamination course of that exchanges a part of the fabric for water, the ensuing catalyst presents as a viable various to iridium-based catalysts.
Extra info:
Ranit Ram et al, Water-hydroxide trapping in cobalt tungstate for proton change membrane water electrolysis, Science (2024). DOI: 10.1126/science.adk9849. www.science.org/doi/10.1126/science.adk9849
Quotation:
New catalyst unveils the hidden energy of water for inexperienced hydrogen technology (2024, June 20)
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