Light falls on a material. And suddenly chemical energy is created - for example in the form of hydrogen or other high-energy substances. Sounds like magic, but it's science. Researchers from Saxony have come a great deal closer to it.
This process is called photocatalysis. Some materials can capture sunlight and use this energy to trigger chemical reactions. Like a turbo for chemistry, powered by the sun. For example, water could be split into hydrogen, a clean energy source. Or convert CO₂ into useful raw materials. The production of important chemicals such as hydrogen peroxide could also become more sustainable in this way.
A team led by the Center for Advanced Systems Understanding (CASUS) at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) has now taken an important step. The researchers in Görlitz have developed a reliable computational method to better understand a promising group of materials known as polyheptazine imides. These are wafer-thin, layer-like compounds from the carbon nitride family, i.e. materials made of carbon and nitrogen atoms. They are cheap to produce, non-toxic and heat-resistant. Above all, however, they react to visible light.
Calculating instead of guessing
This is where the new method comes into play. The team developed a computer-aided process that precisely predicts how a material reacts to light. The decisive factor here is that it not only takes into account the resting state of a material, but also excited states. In other words, precisely those moments when the light strikes and electrons start to move.
The scientists analyzed a total of 53 different metal ions and investigated how they change the structure and electronic properties of the material. They then produced eight of them in the laboratory and tested them for photocatalytic reactions, among other things. The result was clear: the calculations matched the experiments. "If there were any doubts that polyheptazine imides are among the most promising platforms for next-generation photocatalysis technologies, this work has dispelled them," concludes Kühne.
This could be significant for the energy transition. Anyone who can convert sunlight directly into fuel or other chemical energy sources does not need huge batteries or costly detours. Nature shows us how with photosynthesis. Science is working on replicating it.
Original publication:
Z. Hajiahmadi, A. L. Presti, S. Shahab Naghavi, M. Antonietti, C. M. Pelicano, T. D. Kühne: Theory-Guided Discovery of Ion-Exchanged Poly(heptazine imide) Photocatalysts Using First-Principles Many-Body Perturbation Theory, Journal of the American Chemical Society, 2026
