New Energies, new possibilities

AEM 수전해 셀의 성능과 안전성 높여

수전해 셀은 물을 전기화학적으로 분해해 수소를 생산하는 기술이다. 탄소 중립 시대를 위한 필수 에너지 변환 기술인데 문제는 수소를 생산하는데 큰 비용이 들어간다는 점이다. 고가의 백금 사용량이 크게 요구되는 한계가 있었다.

국내 연구팀이 백금 사용량을 10분의 1로 줄여 수전해 셀의 경제성을 높이는 데 성공했다. 이번 연구에서 측정한 수전해 셀 성능은 미국 에너지부(Department of Energy, DOE)가 제시한 수전해 셀 성능과 귀금속 사용량의 2026년 목표치를 유일하게 충족시켰다고 평가받았다.

한국과학기술원(KAIST, 총장 이광형)은 생명화학공학과 이진우 교수 연구팀이 화학과 김형준 교수 연구팀과 공동연구를 통해 음이온 교환막 기반 수전해 셀의 성능과 안정성을 획기적으로 높이는 고성능 고안정성 귀금속 단일 원자 촉매를 개발했다고 31일 발표했다.

연구팀은 귀금속 촉매의 열화 메커니즘을 역이용하는 ‘자가조립원조 귀금속 동적배치’ 전략을 개발했다. 이 방법은 1000℃ 이상의 고온에서 귀금속이 자발적이고 선택적으로 탄화물 지지체에 단일원자로 분해돼 안정적으로 충분히 담기는 합성 기술이다. 상용 백금 촉매와 비교했을 때 10분의 1 수준의 백금 사용량으로도 더 높은 성능과 안정성을 구현했다.

단일 원자 촉매는 금속 원자가 지지체 표면에 고립된 형태로 담겨 높은 귀금속당 촉매 효율을 나타내는데 기존 저온 환원법에서는 촉매 성능과 안정성 확보에 한계가 있었다.

연구팀은 귀금속 전구체와 고분자 사이의 분자적 상호작용과 귀금속-지지체 사이의 상호작용을 응용해 자가조립원조 귀금속 동적배치라는 새로운 단일 원자 촉매합성 메커니즘을 제시했다.

연구팀은 이 합성 기술을 통해 백금뿐 아니라 이리듐, 팔라듐, 로듐 등 다양한 귀금속 단일 원자 촉매에도 적용 가능성을 입증했다.

개발된 백금 단일 원자 촉매의 경우, 염기 조건 수소 생성반응에서 높은 안정성을 가지며 높은 밀도의 귀금속 활성점을 통해 우수한 수소 생산 성능을 보였다. 이 결과 상용 백금 촉매 대비 5배 높은 귀금속당 수소 생산 성능을 구현할 수 있었다.

연구팀은 개발 촉매의 상용성 평가를 위해 음이온 교환막 기반 수전해 셀에 적용했다. 개발된 백금 단일 원자 촉매는 상용 백금 촉매보다 10분의 1 백금 사용량에도 불구하고 그를 능가하는 3.38A/㎠(@ 1.8 V)의 높은 성능을 기록했다.

1A/㎠의 산업용 전류밀도에서도 우수한 안정성을 나타냈다. 이 성능은 미국 에너지부가 제시한 수전해 셀 성능과 귀금속 사용량의 2026년 목표치를 충족시키는 유일한 음이온 교환막 기반 수전해 셀 성능으로 평가받는다.

제1 저자인 김성빈 연구교수는 “이번 기술은 수전해 셀의 원가를 크게 절감시키는 기술”이라며 “이번 연구에서 제시된 자가조립원조 귀금속 동적배치 전략은 수전해 셀뿐만 아니라 다양한 귀금속 기반 촉매 공정에도 응용할 수 있어 산업적 파급력이 클 것으로 보인다”고 말했다.

KAIST 생명화학공학과 김성빈 연구교수가 주도하고, 울산과학기술원(UNIST) 에너지화학공학과 신승재 교수, 한국과학기술연구원(KIST) 수소연료전지센터 김호영 박사가 공동 제1 저자로 참여한 이번 연구(논문명 : Self-assembly-assisted dynamic placement of noble metals selectively on multifunctional carbide supports for alkaline hydrogen electrocatalysis)는 국제 학술지 ‘에너지 인바이론멘탈 사이언스 (Energy & Environmental Science)’ 1월 18권에 출판됐다. 후면 표지논문(inside back cover)으로 선정됐다.

카이스트, 백금 사용량 1/10로 줄이는 단일 원자 촉매 개발

New water splitting catalyst makes green hydrogen without expensive metals

ANEMEL researchers have created a catalyst for water splitting that’s efficient and stable, without relying on scarce platinum group metals (PGMs). The study, recently published in Energy & Environmental Science, reports a high-performance PGM-free catalyst for the cathode in water electrolysis, responsible for the reaction that creates green hydrogen.

Current anion exchange membrane (AEM) water electrolyzers rely on PGMs, which are scarce and expensive. Specifically, these metals are used as catalysts at the cathode, where hydrogen is generated. However, ANEMEL AEM electrolyzers avoid PGMs, opting instead for more abundant metals such as nickel. This is essential to enable the wide adoption of electrolyzers: it helps to decrease the cost of electrolyzer components and improve their recyclability, reducing waste and providing a competitive advantage.

This requires investigating innovative ways to ensure electrolyzers perform at least as well, if not better than, those made with PGMs. After all, platinum and other metals in this group offer excellent activity and stability, especially at high current densities in electrolyzer environments, something PGM-free catalysts still don’t.

To understand the achievement, the researchers define two concepts: self-supported catalyst and electrodeposition. A self-supported catalyst is a type of catalyst formed by growing it directly on a support, known as a gas diffusion layer (GDL). The GDL allows gases to diffuse while providing a conductive pathway and can be made of various materials. These include carbon paper, and nickel foam, felt and mesh.

Electrodeposition is a widely used technique in applications such as watches and boats, anywhere a metal coating is needed. It works through electrolysis, a process that uses electrical energy to drive a chemical reaction. Two electrodes, the working electrode—where the GDL is located—and a counter electrode, are immersed in an electrically conductive solution called the electrolyte. By applying a current between the two, ions in the solution, which serve as precursors of the catalyst, migrate towards the working electrode “growing” the catalyst.

Here, ANEMEL researchers grew a catalyst made from nickel and molybdenum, both abundant metals. The novelty lies in the method and variables involved in achieving a high-performing catalyst, since this combination of metals had already been used in similar reactions before.

The first author of the paper Ariana Serban, doctoral researcher at ANEMEL partner the École Polytechnique Fédérale de Lausanne (EPFL), in Switzerland, says :

I’ve been working on this catalyst for a long time now. This work has been accumulated over time—we optimized the method, the composition of the electrodeposition bath, and the substrates we are using for the GDL,

Researchers chose carbon paper as the substrate for the GDL. This decision was made after confirming that nickel foam, felt and mesh weren’t the best options. For example, the latter created small holes in the membrane, with the consequent short circuit. Regarding the method, its novelty lies in the composition of the electrodeposition bath and the use of high-current density for deposition.

Serban explains,

Electrodeposition baths frequently used in the literature often include a buffering agent, such as boric acid, to stabilize the pH.

“We haven’t used this. That’s why the technique is special. We rely solely on an electrolyte with high conductivity. This high conductivity is crucial as it affects the electrodeposition process,”

Such high conductivity allowed the use of a higher deposition current density, a deliberate choice to achieve a more compact and thicker electrode structure.

The result is a catalyst with remarkable activity. In particular, it enabled electrolyzers to operate stably at current densities as high as 3 A/cm² —the increased stress during high current operations can serve as a rapid assessment tool for the device’s robustness, eliminating the need for lengthy tests spanning thousands of hours.

Such performance is comparable to benchmark platinum catalysts, even with a slightly superior stability. This means ANEMEL not only developed a PGM-free HER catalyst, but also a catalyst exceeding state-of-the-art catalysts. According to Serban, this result ranks among the top 100, or even top 50, in terms of performance for non-PGM catalysts.

Characterization of the catalyst revealed a structural change during the reaction that explained the good results.

She explains,

There was a reorganization of the surface, where bulk molybdenum atoms migrated to the surface, helped by distortions in the bulk,

Some of these atoms become oxidized—they lose electrons—and these oxidized species contribute to the water-splitting process. This result brings us one step closer to large-scale green hydrogen production.

New water splitting catalyst makes green hydrogen without expensive metals - Hydrogen Central

An oxide-promoted, self-supported Ni4Mo catalyst for high current density anion exchange membrane water electrolysis - Energy & Environmental Science (RSC Publishing)

Green hydrogen report targets 58% cut in production costs

Long-duration energy storage, decarbonised steel production, clean aviation – the opportunities from affordable green hydrogen are many and varied. At the moment, however, that goal is a long way off.

A new report from RenewableUK and Hydrogen UK aims to change that. “Splitting the Difference – Reducing the Cost of Green Hydrogen to Accelerate Deployment” includes recommendations that the trade associations say could drive the cost of production down from £241 per megawatt hour (MWh), which was achieved in the first Hydrogen Allocation Round in 2023, to less than £100/MWh.

The UK has “massive potential” to use renewable electricity to produce hydrogen in electrolysers that split water into hydrogen and oxygen, the report said, and key measures could unlock economies of scale.

The report announcement said,

Affordable green hydrogen will be an essential tool for building the energy system of the future, providing long-duration storage for surplus electricity, and also for decarbonising sectors such as steel, chemicals and shipping,

Recommendations include removing barriers to locating hydrogen production at renewable energy plants and incentivising electrolysis to happen when electricity is cheapest. The report also calls for the government to reform the hydrogen production business model to secure the maximum amount of investment, and to introduce an “ambitious” strategy to enable development of a hydrogen transmission network, with pipelines linking Scotland to England and Wales to optimise the availability of green hydrogen.

The announcement said,

For hydrogen to realise its full potential in helping the UK to decarbonise, it must become more affordable as it gets deployed at scale.

“Like similar nascent technologies in their early stages, green hydrogen has an enormous potential for cost reduction. As the UK scales up production with the help of the recommendations identified in this report, the cost of electrolytic hydrogen production is expected to drop dramatically,”

The price of electricity currently represents about 70% of the final cost of green hydrogen, so reducing it is “imperative”, the trade association said. Another one of the 11 key recommendations is to reduce the charges that project developers have to pay for access to the grid.

Dan McGrail, chief executive of RenewableUK, said :  

Green hydrogen generated from renewables will play an important role in helping the government to achieve its clean power mission,

“It can add vital flexibility to our energy system, as it can be stored and used whenever it’s needed. This report shows that to realise this strong potential, the government will need to work with RenewableUK and Hydrogen UK to establish innovative business models to attract private investment, including strike prices which reflect the fact that this technology is still at an early stage, and incentives for developers to build electrolysers alongside wind and solar farms to cut costs. Enacting the key measures set out in this report will enable the UK’s nascent green hydrogen industry to build on its global lead in this technology, driving down costs significantly in the long term, creating thousands of new jobs and generating billions of pounds in economic activity before the end of this decade.”

Clare Jackson, CEO of Hydrogen UK, said:

This report… marks pivotal steps towards achieving our national goals in energy security and [the] clean energy transition by making hydrogen an economically viable option.

Green hydrogen report targets 58% cut in production costs - Hydrogen Central

The electrolyser will be installed in a test stand at the Turbocharger Performance Centre (TPC) on the Augsburg site of MAN Energy Solutions (MAN ES), where it will generate data in test operation for continuous optimisation. With the demonstration plant, Quest One is turning large electrolysers into a tangible experience. Operational constraints often mean that these plants cannot be viewed while they are in use at customers' sites. The joint project aims to change this: From mid-2025, it will be possible for potential customers as well as for project developers and EPCs to visit the demonstration plant. This will give them valuable insights into the construction phases, dimensions, inner workings and infrastructure.

A second objective of the joint project with MAN Energy Solutions is to continuously optimise the scale of PEM electrolysers on the base of field data and to further refine both the system operation as well as the installation and service concept.

“It is essential to have industrial scale electrolysers to meet the huge demand for green hydrogen in the future. With our new hydrogen demonstration plant we will show that the technology for industrial scale hydrogen production already exists. In particular, our PEM electrolysis technology is perfectly suited for use with renewable energy sources and stands out with a high hydrogen quality. Prospects can now experience these advantages at our demonstration plant,” said Jürgen Klöpffer, Chairman of the Advisory Board of Quest One and member of the Executive Board of MAN Energy Solutions.

“Our MHP is an essential building block for decarbonising of the industrial sector. The scalable system can be flexibly adapted to increasing hydrogen demands as the industry ramps up. The demonstration plant is an important means for us to further optimise the performance and operating parameters of the MHP. This will ensure that our products continue to produce green hydrogen in a reliable and efficient way in the future,” explained Michael Meister, COO at Quest One.

Joint project implementation

The project underlines the joint efforts of Quest One and MAN Energy Solutions to make green hydrogen a reliable fuel for the decarbonisation of the industry. Through the jointly operated test stand, both partners are further expanding their knowledge and skills in the construction, project management, operation and maintenance of large scale industrial electrolysers. Quest One is thus also taking a further step in scaling up its own product portfolio for projects ranging from ten to several hundred megawatts of electrolysis capacity. Continuously increasing electrolysis capacity is an important prerequisite for the company's goal of avoiding up to one percent of global greenhouse gas emissions by 2050 through the implementation of its products.

Construction started at the end of 2024 with the installation of the freshwater treatment. The plant will be assembled over the course of 2025, so test operations can start by the beginning of 2026. Potential business partners will be able to already gain insights into the construction phase and visit the plant onsite in Augsburg in 2025.

Industrial scale hydrogen production

The MHP is currently the largest PEM electrolyser in Quest One's product portfolio. Its scalable modular system makes it particularly suitable for industrial production of green hydrogen. Module blocks with an output of 10 MW can be expanded and combined to create plants with an electrolysis capacity from 10 to several hundred megawatts. The system is optimised for easy indoor installation on preassembled skids. Each 10-megawatt block is equipped with integrated process water treatment and an electrical power supply.

Funding under the PEP.IN programme

The development of the demonstration plant is being funded as part of the PEP.IN research project, a sub-project of the H2Giga hydrogen lighthouse project of the German Federal Ministry of Education and Research (BMBF). PEP.IN is exploring new processes for the series production of PEM electrolysers. It looks at the entire value chain from stack production to final assembly. The aim is to make green hydrogen affordable and competitive. The scope of funding particularly covers feasibility and viability studies as well as the planning of the necessary infrastructure.

Quest One and MAN Energy partner on large scale electrolyser | Global Hydrogen Review