Periodic Reporting for period 1 - P2XSACat (Single-atom decorated 2D catalysts for power-to-X conversion and sustainable future)
Période du rapport: 2023-11-15 au 2025-08-14
Renewable energy has been at the forefront of scientific and technological advancements for decades, driven by the urgent need to mitigate global warming and reduce dependence on fossil fuels. Among all renewable energy carriers, hydrogen plays a particularly important role because it can be produced from water using electricity from renewable sources and used without releasing harmful emissions. Despite these advantages, the widespread adoption of hydrogen technologies remains limited by the lack of efficient, affordable, and durable catalysts that can accelerate key electrochemical reactions, such as water splitting.
Traditionally, noble metals such as platinum, rhodium, and iridium exhibit outstanding catalytic performance; however, they are rare and costly. To overcome this, scientists are seeking ways to utilize every atom of these precious materials more efficiently. One promising concept is single-atom catalysis, in which individual metal atoms are dispersed on a conductive support. This approach maximizes catalytic efficiency, reduces material waste, and opens new possibilities for designing highly active and tunable catalysts at the atomic scale.
The P2XSACat project focuses on exploring this frontier by developing new two-dimensional catalytic materials based on MXenes— a class of transition-metal carbides and nitrides with remarkable properties. MXenes have a high surface area, excellent electrical conductivity, and a tunable surface chemistry that allows metal atoms to attach firmly to their surface. These features make them ideal platforms for supporting single-atom catalytic centers. However, MXenes are also chemically sensitive and tend to oxidize easily, which makes their modification a major scientific challenge.
To address this, the project focused on three main directions that together define its pathway to impact. First, it aimed to develop new, energy-efficient synthesis methods that would allow decoration of MXene nanoflakes with isolated metal atoms. Second, the project sought to understand the structure of these new materials and how it relates to their properties. The third focus was to evaluate the electrocatalytic performance of the developed materials, primarily in the hydrogen evolution reaction, a crucial process in the production of green hydrogen.
Traditionally, noble metals such as platinum, rhodium, and iridium exhibit outstanding catalytic performance; however, they are rare and costly. To overcome this, scientists are seeking ways to utilize every atom of these precious materials more efficiently. One promising concept is single-atom catalysis, in which individual metal atoms are dispersed on a conductive support. This approach maximizes catalytic efficiency, reduces material waste, and opens new possibilities for designing highly active and tunable catalysts at the atomic scale.
The P2XSACat project focuses on exploring this frontier by developing new two-dimensional catalytic materials based on MXenes— a class of transition-metal carbides and nitrides with remarkable properties. MXenes have a high surface area, excellent electrical conductivity, and a tunable surface chemistry that allows metal atoms to attach firmly to their surface. These features make them ideal platforms for supporting single-atom catalytic centers. However, MXenes are also chemically sensitive and tend to oxidize easily, which makes their modification a major scientific challenge.
To address this, the project focused on three main directions that together define its pathway to impact. First, it aimed to develop new, energy-efficient synthesis methods that would allow decoration of MXene nanoflakes with isolated metal atoms. Second, the project sought to understand the structure of these new materials and how it relates to their properties. The third focus was to evaluate the electrocatalytic performance of the developed materials, primarily in the hydrogen evolution reaction, a crucial process in the production of green hydrogen.
The P2XSACat project advanced the development of innovative two-dimensional catalytic materials for sustainable energy applications. The research focused on synthesizing and characterizing single-atom-decorated MXenes—transition metal carbides capable of supporting highly active and stable catalytic sites for hydrogen production.
The project successfully developed a microwave-assisted solvothermal synthesis method that enables decoration of MXene nanoflakes with atomically dispersed metal centers. This approach offers significant advantages over traditional techniques by reducing synthesis time, energy consumption, and processing complexity while preserving the original structure of the 2D materials.
Comprehensive structural and chemical characterization was performed using X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy.
Electrocatalytic studies demonstrated a clear improvement in hydrogen evolution reaction performance for MXenes decorated with single atoms of rhodium, platinum, and ruthenium. The approach was also extended to molybdenum sulfide nanoflakes doped with nickel and cobalt, achieving high efficiency with earth-abundant elements. An optimal concentration of catalytic sites was identified, and the bottlenecks of single-atom electrocatalysis related to diffusion and charge transfer within the electrocatalyst were discussed.
The experimental results were combined with theoretical density functional theory (DFT) modeling. High-resolution X-ray photoelectron spectra of catalytic atoms, supported by DFT modeling, provided a detailed understanding of how single atoms bond to 2D nanoflakes. Another aspect of the collaborative research focused on establishing criteria for identifying catalytic sites with high potential for efficiency. This criterion was developed based on a comparison of hydrogen atom binding efficiency at catalytic sites under different protonation levels of the surrounding catalyst surface and was tested on the catalytic sites observed experimentally.
The project successfully developed a microwave-assisted solvothermal synthesis method that enables decoration of MXene nanoflakes with atomically dispersed metal centers. This approach offers significant advantages over traditional techniques by reducing synthesis time, energy consumption, and processing complexity while preserving the original structure of the 2D materials.
Comprehensive structural and chemical characterization was performed using X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy.
Electrocatalytic studies demonstrated a clear improvement in hydrogen evolution reaction performance for MXenes decorated with single atoms of rhodium, platinum, and ruthenium. The approach was also extended to molybdenum sulfide nanoflakes doped with nickel and cobalt, achieving high efficiency with earth-abundant elements. An optimal concentration of catalytic sites was identified, and the bottlenecks of single-atom electrocatalysis related to diffusion and charge transfer within the electrocatalyst were discussed.
The experimental results were combined with theoretical density functional theory (DFT) modeling. High-resolution X-ray photoelectron spectra of catalytic atoms, supported by DFT modeling, provided a detailed understanding of how single atoms bond to 2D nanoflakes. Another aspect of the collaborative research focused on establishing criteria for identifying catalytic sites with high potential for efficiency. This criterion was developed based on a comparison of hydrogen atom binding efficiency at catalytic sites under different protonation levels of the surrounding catalyst surface and was tested on the catalytic sites observed experimentally.
The P2XSACat project achieved significant progress in developing and understanding single-atom-decorated materials for clean energy applications. The work provided new insights into how atomic-scale structure determines catalytic performance and introduced innovative methods for the sustainable synthesis of materials.
A key technical achievement was the development of a microwave-assisted solvothermal synthesis technique that enables the precise decoration of two-dimensional MXene nanoflakes with atomically dispersed metal sites. This method offers substantial advantages over conventional multi-step or high-temperature processes. Microwave heating allows extremely fast and uniform temperature control, significantly reducing reaction time and energy consumption while preventing oxidation of the sensitive MXene surfaces. The process can be carried out directly in liquid suspensions, which opens the possibility for continuous catalyst production and easy integration into industrial workflows for electrode fabrication. This makes the technique highly attractive for future scale-up and potential commercial applications in green hydrogen or other Power-To-X conversion technologies.
In parallel, the project demonstrated that combining high-resolution XPS analysis with DFT modeling provides a powerful and accurate method for determining the real structure of single-atom catalytic sites.
A new theoretical criterion was introduced to identify the most efficient catalytic sites by analyzing changes in the Gibbs free energy of hydrogen adsorption during the reaction. When this energy shifts from negative to positive as hydrogen transfer occurs from a catalyst surface without bonded hydrogen atoms to a surface fully covered with oxygen, it indicates a middle state where Gibbs energy equals zero. This means hydrogen binds neither too strongly nor too weakly to the surface, creating ideal conditions for hydrogen evolution.
These results create a robust scientific and technological foundation for future innovation in sustainable catalysis. The next steps should focus on scaling the microwave solvothermal process, validating the materials in real electrochemical systems, and establishing industrial collaborations to accelerate the transition of this research toward practical, low-emission hydrogen technologies that align with the European Green Deal objectives.
A key technical achievement was the development of a microwave-assisted solvothermal synthesis technique that enables the precise decoration of two-dimensional MXene nanoflakes with atomically dispersed metal sites. This method offers substantial advantages over conventional multi-step or high-temperature processes. Microwave heating allows extremely fast and uniform temperature control, significantly reducing reaction time and energy consumption while preventing oxidation of the sensitive MXene surfaces. The process can be carried out directly in liquid suspensions, which opens the possibility for continuous catalyst production and easy integration into industrial workflows for electrode fabrication. This makes the technique highly attractive for future scale-up and potential commercial applications in green hydrogen or other Power-To-X conversion technologies.
In parallel, the project demonstrated that combining high-resolution XPS analysis with DFT modeling provides a powerful and accurate method for determining the real structure of single-atom catalytic sites.
A new theoretical criterion was introduced to identify the most efficient catalytic sites by analyzing changes in the Gibbs free energy of hydrogen adsorption during the reaction. When this energy shifts from negative to positive as hydrogen transfer occurs from a catalyst surface without bonded hydrogen atoms to a surface fully covered with oxygen, it indicates a middle state where Gibbs energy equals zero. This means hydrogen binds neither too strongly nor too weakly to the surface, creating ideal conditions for hydrogen evolution.
These results create a robust scientific and technological foundation for future innovation in sustainable catalysis. The next steps should focus on scaling the microwave solvothermal process, validating the materials in real electrochemical systems, and establishing industrial collaborations to accelerate the transition of this research toward practical, low-emission hydrogen technologies that align with the European Green Deal objectives.