Green hydrogen is considered key to a climate-friendly transformation of our industries and energy systems, but thus far its production has been expensive, complex, and tied to grid infrastructure. This is exactly where photreon, a KIT spin-off, aims to make a difference. It has developed a photoreactor panel that generates hydrogen directly from sunlight and water – without electrolyzers or electrical power. “We avoid the detour through electrically powered electrolysis, producing chemical energy from sunlight and water,” said photreon co-founder Paul Kant from KIT’s Institute for Micro Process Engineering (IMVT). Kant also noted that photreon’s modular panels simplify solar hydrogen production while making it economically scalable.
Direct Solar Conversion without Electricity
The approach taken by photreon is based on photocatalysis, a process in which light triggers a chemical reaction directly instead of being used to generate electricity as in photovoltaic systems. Specially designed, light-sensitive materials absorb energy from sunlight, exciting electrons into an activated state. These charge carriers split water molecules (H₂O) into hydrogen (H₂) and oxygen (O₂). “In a single step, we’re replacing photovoltaics and electrolyzers with our photoreactor panel,” said Maren Cordts, who is also a co-founder and a staff member of IMVT. “For the production of green hydrogen, that means much lower complexity and system costs.”
KIT has filed a patent application for the photoreactor panel implemented by photreon. With its special design, the panel guides sunlight to its interior for optimal irradiation of the active material inside, which then drives the reaction that splits the water molecules. “We designed the reactor geometry to optimize the interplay of light transport, chemical reaction, and removal of the reaction products, and we’re demonstrating that with our one-square-meter prototype,” Kant said. The modular design is tailored for mass production using standard processes and low-cost materials, and it can be used on a small scale or expanded to larger areas.
From Rooftops to Solar Hydrogen Farms
The panels can be used where supplying hydrogen has previously been too expensive or logistically difficult, for instance in medium-sized companies wanting to cover their future needs on-site (e.g. specialty chemicals, food production, or metalworking) or in large-scale solar projects in regions with abundant sunlight. “In places without connections to power grids or a hydrogen network, our technology opens up new possibilities for local production,” Cordts said. Possible applications range from supplying distributed production sites to industrial production in sunny regions for the international market.
More about the KIT Energy Center
In close partnership with society, KIT develops solutions for urgent challenges – from climate change, energy transition and sustainable use of natural resources to artificial intelligence, sovereignty and an aging population. As The University in the Helmholtz Association , KIT unites scientific excellence from insight to application-driven research under one roof – and is thus in a unique position to drive this transformation. As a University of Excellence, KIT offers its more than 10,000 employees and 22,800 students outstanding opportunities to shape a sustainable and resilient future. KIT – Science for Impact.