New Energies, new possibilities

An international team of researchers from Forschungszentrum Jülich, Lawrence Berkeley National Laboratory, Imperial College London and others, are refining the design principles of metal exsolution catalysts to drive advancements in renewable energy technologies.

Efficient and durable low-cost catalysts are essential for green hydrogen production and related chemical fuels production, both vital technologies for the transition to renewable energy. Research in this field increasingly focuses on metal exsolution reactions to fabricate catalysts with improved properties. A new study led by Forschungszentrum Jülich, in collaboration with international institutions, has unveiled how oxygen vacancies in oxide materials influence the stability of metal nanoparticles on the surface of such materials, which are critical to catalyst performance. The findings, published in Nature Communications, reveal practical strategies to enhance catalyst durability and make green hydrogen production more competitive.

Scientific Results

The study focused on the process of metal exsolution, a relatively new procedure where metal dopants initially part of the oxide lattice in oxide materials are released during thermal reduction to form nanoparticles on the oxide surface. These nanoparticles, in combination with the oxide substrate, create highly active interfaces that are crucial for catalyzing electrochemical reactions, such as water splitting for green hydrogen production.

The researchers demonstrate that oxygen vacancies—defects in the oxide crystal lattice where oxygen atoms are missing—play a pivotal role in nanoparticle stability. Oxides with high concentrations of oxygen vacancies that are used, for example, in fuel cells and electrolyzer cells, exhibit increased surface mobility of nanoparticles at elevated temperatures, which are typical for operation, causing them to coalesce into larger particles. This coalescence reduces the density of active sites, thereby diminishing the catalyst's efficiency. Conversely, oxides with lower concentrations of oxygen vacancies stabilize the nanoparticles, preventing coalescence and maintaining catalytic activity over time.

The team also identified a simple yet effective method to mitigate these effects. Introducing water vapor into the reaction environment slightly increases oxygen partial pressure, reducing the number of oxygen vacancies at the interface between the oxide and nanoparticles. This adjustment enhances nanoparticle stability and prolongs catalyst durability. Additionally, modifying the composition of the oxide material to inherently decrease oxygen vacancy concentration provides another viable approach for achieving long-term stability.

Social and Scientific Relevance

These findings have significant implications for the development of renewable energy systems. Exsolution catalysts are being discussed as promising candidates to replace conventional materials, particularly in solid oxide cells. Solid oxide cells are critical for both producing green hydrogen, an essential energy carrier for storage and transport, and converting it back into electricity at the highest efficiency levels. The durability of catalysts directly impacts the economic and operational feasibility of these devices.

Although metal exsolution reactions offer a promising approach for developing catalysts with enhanced properties, the limited durability of these catalysts—prone to structural and chemical degradation under operating conditions—remains a significant barrier to their practical application in green energy technologies. By addressing the issue of nanoparticle coalescence, this research could lead advance the viability of these novel catalysts.

Further Details

The research was a collaborative effort involving 20 scientists from institutions across Germany, the United States, and the United Kingdom. The study began during the collaborative doctoral project of lead author Dr. Moritz L. Weber at Forschungszentrum Jülich’s Peter Grünberg Institute (PGI-7) and Institute of Energy Materials and Devices (IMD-2), in collaboration with Imperial College London, and was supported by a DAAD scholarship. Dr. Weber continued his research as a Collaborative Postdoctoral Fellow at Lawrence Berkeley National Laboratory, working with experts at the Advanced Light Source and Dr. Felix Gunkel’s group at the PGI-7 in Jülich as well as Dr. Dylan Jennings from IMD-2 and colleagues at the Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) in Jülich.

The interdisciplinary nature of the study was essential for achieving its results, combining expertise in materials science, catalysis, and electrochemistry. Published in Nature Communications, the study provides actionable strategies for improving catalyst durability through adjustments in reaction conditions and material compositions and represents a significant step forward in the development of technologies for renewable energies.

Enhancing Catalyst Stability for Green Hydrogen

AES Chile has submitted the Environmental Impact Study (EIA) for the INNA project, its first industrial-scale green hydrogen and ammonia initiative in the country. The project, located in Taltal, Antofagasta region, which is in an initial development stage, is aligned with Chile's National Green Hydrogen Strategy.

"Although this project is in an early stage of development and the investment decision will have to be made later, the presentation of the EIA is a fundamental step to ensure the viability of the initiative," said Javier Dib, General Manager of AES Andes.

"AES Chile is accelerating the future of energy, creating opportunities that diversify Chile's energy matrix and support the country's sustainable energy goals. As with all of our projects, our partnership with local communities and stakeholders is a priority. We want to strengthen local development, while maintaining the highest environmental and safety standards," Dib continued.

To support this project, a Memorandum of Understanding (MOU) was signed between AES Andes and Samsung C&T, a major Korean company with experience in energy and construction, which was recently awarded the contract for the first green ammonia receiving terminal in Korea.

The two companies are currently evaluating the joint development of the project, focusing on opportunities to produce green hydrogen for domestic consumption or for export to international markets.

The project submitted to the SEA includes the production of green hydrogen and ammonia, as well as the development of solar, wind and battery storage energy, in line with the needs of the project and to support the country's electricity generation.

"The company has carried out dedicated community engagement work with special attention to the Chango communities present in the area, as well as other relevant actors. We will maintain this commitment to collaborative work as we move forward with the environmental processing of Inna," said Luis Sarrás, Vice President of International Green Hydrogen at AES.

(Bloomberg) -- Green hydrogen has been touted by politicians and business leaders alike as a key fuel for a carbon-free future. But it will remain far more expensive than previously thought for decades to come, according to a new estimate from BloombergNEF.

Hydrogen companies worldwide are already struggling with canceled projects and sluggish demand. In the US, billions of dollars of projects have been stalled waiting for President Joe Biden’s administration to issue final rules for a tax credit meant to spur production.

BNEF had in the past forecast steep declines in the price of green hydrogen, which is made by splitting it from water with machines called electrolyzers running on renewable power. But in its forecast published Monday, the firm more than tripled its 2050 cost estimate, citing higher future costs for the electrolyzers themselves. BNEF now forecasts green hydrogen to fall from a current range of $3.74 to $11.70 per kilogram to $1.60 to $5.09 per kilogram in 2050.

For comparison, the most common form of hydrogen used today — stripped from natural gas, with the carbon emissions vented into the atmosphere — costs from $1.11 to $2.35 per kilogram, according to BNEF. The research firm expects prices for such “gray” hydrogen to remain largely the same through mid-century.

“The higher costs for producing green hydrogen without any subsidies or incentives means it will continue to be challenging to decarbonize hard-to-abate sectors, such as chemicals and oil refining, with hydrogen produced via electrolysis powered by renewables,” said BNEF analyst Payal Kaur.

Those industries along with steel mills and power plants have been tagged as possible end users of the gas. But doing so would require expensive new equipment, which has stunted demand. 

Only two markets — China and India — are likely to see green hydrogen become cost-competitive, according to BNEF. There, the cleaner fuel will reach a comparable price to gray hydrogen by 2040. 

The forecast puts Biden’s goal of driving US hydrogen costs down to $1 per kilogram by 2031 out of reach. Many analysts consider that price essential to convincing potential customers to start using the fuel. BNEF took an in-depth look at how green hydrogen will fare in New York, Texas and Utah. The report found that Texas will create the cheapest green hydrogen but costs will only fall from $7.22 per kilogram today to $4.82 in 2030. If Biden’s planned tax credit of $3 per kilogram is included, Texas hydrogen costs could fall below $1 by 2040, according to the forecast.

The fate of US hydrogen policies remains uncertain, with President-elect Donald Trump set to take office in January. Although industry executives remain hopeful he will continue many of Biden’s initiatives — in part because oil companies are interested in hydrogen — Trump has said little about it. His threatened tariffs on imported products could boost the price of foreign-made electrolyzers, but BNEF’s price forecast did not take tariffs or subsidies into account.

Slow hydrogen demand growth, meanwhile, has forced companies worldwide to scale back their ambitions. Equinor ASA, Shell PLC and Origin Energy Ltd. all canceled hydrogen production projects this year due to a lack of buyers.  

Green Hydrogen Prices Remain High for Decades