Periodic Reporting for period 1 - SCI-PHI (Single-atom Catalysis in Photocatalytic Investigations)
Reporting period: 2023-09-01 to 2025-08-31
This project set out to investigate the role of individual atoms in light-driven chemical reactions, a field known as photocatalysis. Photocatalysis is a promising technology for clean energy because it uses sunlight to power chemical reactions, for example to split water into hydrogen and oxygen or to convert carbon dioxide into useful fuels. However, despite its potential, photocatalysis remains poorly understood on a fundamental level. Many questions remain about how light energy is absorbed, how charges move inside a material, and how molecules interact with the surface.
A particularly exciting avenue is the use of so-called single-atom catalysts: semiconductor materials that carry individual metal atoms anchored to their surface. These atoms can act as highly efficient reaction centers. Yet, because the field is new, little is known about their precise function. Our project addressed this knowledge gap by studying photocatalysis under highly controlled conditions, using advanced physical chemistry tools to “zoom in” on the atomic scale.
A particularly exciting avenue is the use of so-called single-atom catalysts: semiconductor materials that carry individual metal atoms anchored to their surface. These atoms can act as highly efficient reaction centers. Yet, because the field is new, little is known about their precise function. Our project addressed this knowledge gap by studying photocatalysis under highly controlled conditions, using advanced physical chemistry tools to “zoom in” on the atomic scale.
The first step was to adapt our laboratories for photocatalysis. We designed and built a flexible optical system, including a laser and mirrors, that could be connected to different vacuum chambers without breaking the vacuum. This setup creates a well-defined beam of light on the catalyst, avoiding stray-light effects and providing reproducible experimental conditions.
We then selected suitable model materials. Titanium dioxide (TiO2) was used as a benchmark, as it is the most widely studied photocatalyst, while hematite (Fe2O₃) was introduced as a new model system in our laboratory. Both materials are known to stabilize single atoms under certain conditions.
Experiments on TiO2 demonstrated that our setup works as intended: we were able to trigger and measure light-driven reactions with simple probe molecules such as oxygen and methanol. These experiments also validated a new infrared spectroscopy system developed in our group, which is an important tool for identifying atoms and molecules on surfaces. On Fe2O₃ we successfully carried out similar photocatalytic tests, confirming its suitability as a model system. The first experiments with single atoms anchored to Fe2O₃ are ongoing, showing promising early results.
We then selected suitable model materials. Titanium dioxide (TiO2) was used as a benchmark, as it is the most widely studied photocatalyst, while hematite (Fe2O₃) was introduced as a new model system in our laboratory. Both materials are known to stabilize single atoms under certain conditions.
Experiments on TiO2 demonstrated that our setup works as intended: we were able to trigger and measure light-driven reactions with simple probe molecules such as oxygen and methanol. These experiments also validated a new infrared spectroscopy system developed in our group, which is an important tool for identifying atoms and molecules on surfaces. On Fe2O₃ we successfully carried out similar photocatalytic tests, confirming its suitability as a model system. The first experiments with single atoms anchored to Fe2O₃ are ongoing, showing promising early results.
The project has delivered both technical and scientific outcomes. Technically, we have shown how to upgrade standard vacuum chambers for photocatalysis with minimal effort, a result that can be taken up by other laboratories internationally. Scientifically, we established a solid foundation for investigating single atoms in photocatalysis, providing data on model systems and refining methods for probing atomic-scale reactions.
The potential impact of this work is significant. By clarifying the role of single atoms in driving chemical reactions with light, our results contribute to the rational design of more efficient catalysts. This knowledge will help to accelerate the development of solar-driven energy technologies such as hydrogen production and CO2 conversion, which are directly linked to the European Green Deal and the EU’s climate neutrality goals.
The potential impact of this work is significant. By clarifying the role of single atoms in driving chemical reactions with light, our results contribute to the rational design of more efficient catalysts. This knowledge will help to accelerate the development of solar-driven energy technologies such as hydrogen production and CO2 conversion, which are directly linked to the European Green Deal and the EU’s climate neutrality goals.