Direct CO₂ capture for solar fuels production

A single, sunlight‑powered process for converting CO₂ from air into fuels and chemicals

Technology

This technology enables direct capture of CO₂ from ambient air and its immediate conversion into valuable syngas (CO + H₂) using sunlight as the sole energy input.
Integrated flow reactor captures CO₂ at night and releases it as a concentrated stream during daytime operation, where it is photochemically converted via a low‑cost, earth‑abundant catalyst system.

Benefits

Energy‑efficient CO₂ utilisation from air: Combines direct air capture and conversion in one system, avoiding the energy‑intensive CO₂ compression, transport and storage steps that constrain most direct air capture (DAC) technologies.
Fully solar‑powered, low‑cost materials: Operates using sunlight and inexpensive catalysts, reducing operating costs and reliance on critical raw materials.
Direct production of industrial syngas: Produces CO/H₂ mixtures directly from air‑captured CO₂, supplying a versatile, drop‑in feedstock for existing fuel and chemical value chains.

Schematics of the system during light-off night operation and during light-on day operation. Source: Nature Energy, 10, 448–459 (2025)

Commercial applications

Carbon utilisation and climate technologies.
Renewable energy and hydrogen ecosystems.
Chemical manufacturing and sustainable fuels.

Opportunity

We are now looking for commercial partners interested in helping us develop this technology.

Founders

Professor Erwin Reisner

Professor Erwin Reisner is the Professor of Energy and Sustainability in the Yusuf Hamied Department of Chemistry at the University of Cambridge, where he also holds a Royal Academy of Engineering Chair in Emerging Technologies. He is also a Fellow of St. John’s College, Cambridge. He is an expert in renewable energy technologies and sustainable chemistry, in particular the sunlight-powered production of sustainable fuels and platform chemicals. His cross-disciplinary research into solar chemistry and circular chemical technologies focuses on the capture and utilisation of the greenhouse gas carbon dioxide as well as the valorisation of plastics and biomass waste to produce green fuels and chemicals for a net zero future.

Erwin and his team have developed concepts and approaches for the integration of synthetic and biological catalysts with photovoltaic light absorbers to enable efficient and selective solar-driven chemical synthesis. The understanding and assembly of such semiconductor-molecule ‘hybrid materials’ and ‘semi-artificial’ biohybrids has led to the construction of autonomous solar-powered prototype devices for direct solar fuel production. Their ‘solar fuels devices’ demonstrated artificial photosynthesis by converting carbon dioxide into carbon monoxide, formic acid, multi-carbon alcohols or acetic acid, while oxidising water to co-produce oxygen gas. Erwin’s team also established ‘solar reforming’ as a practical approach to upcycle lignocellulosic biomass and plastic waste to platform chemicals and fuels. Their concepts and solar-powered prototype devices demonstrated the performance and economic advantages of oxidising solid waste streams instead of oxidising water, making the lab-to-market transition of solar chemistry a realistic long-term prospect. To accelerate the commercialisation of solar reforming, he and his colleagues have protected the underlying core IP and co-founded the start-up company ‘Protonera’. His team has also made contributions to show the potential of heterogeneous semiconductor photocatalysts for green organic synthesis and has reported solar hybrid technologies to demonstrate the benefits of integrated solar chemistry over conventional photovoltaic-electrolyser technologies.

Erwin’s laboratory on solar chemical technologies has been supported by several fellowships and grants such as an EPSRC Career Acceleration Fellowship on bio-inspired solar hydrogen production (2009-2015), the Christian Doppler Laboratory for Sustainable SynGas Chemistry (2012-2019), a European Research Council (ERC) Consolidator Grant on semi-artificial photosynthesis (2016-2023), an ERC/UKRI Advanced Grant on semi-biological domino catalysis (2023-2028) and a Royal Academy of Engineering Chair for tech-transfer of solar reforming (2024-2034). He has received several awards and recognitions for his team’s scientific achievements, such as the Hughes Medal by the Royal Society (2023), the Tilden Prize by the Royal Society of Chemistry (2024) and being named as ClarivateTM Highly Cited Researcher (2024).

Dr Sayan Kar

Dr Sayan Kar completed his bachelor’s and Master’s in chemistry from the Indian Institute of Technology Kanpur in 2015 with distinction. Thereafter, he moved to Los Angeles to pursue his PhD in the group of Prof Surya Prakash and Prof George Olah, working on the Methanol Economy. Upon graduating in 2019, he moved to Israel at the Weizmann Institute of Science as a postdoctoral researcher in the group of Prof David Milstein, working in sustainable homogeneous catalysis. In late 2021, he moved to the University of Cambridge to pursue another postdoc with Prof Erwin Reisner to develop processes for solar air-to-fuel conversion. Since 04/2025, he has been an assistant professor at the Department of Sustainable Energy Engineering at IIT Kanpur.

Sayan’s academic and research career has exceptional accomplishments including six Proficiency and Excellence awards during undergraduate studies at IITK, an All India Rank (AIR) 2 in the CSIR-NET 2013 (Dec) exam and an AIR 8 in the WBJEE 2010 exam, the Weber Award from USC during PhD for outstanding graduate research, and the FGS prize from the Weizmann Institute of Science for exceptional postdoctoral achievements. Sayan have been awarded multiple prestigious fellowships, including the Marie Curie Postdoctoral fellowship by the European Research Council (equivalent of $250,000) and the SAERI postdoctoral fellowship by the Weizmann Institute ($100,000), and grants over 10 million INR ($100,000) in his independent career. He has been prolific in research with 30 published articles in premium journals, including Nature Energy, Nature Catalysis, Joule, JACS, ACS Catalysis, Acc. Chem. Res., which are highly cited (>3200 times, h index 26), and covered by 100+ news outlets. He recently received the Young Scientist Award at 4th Global Conference for Decarbonization of Energy and Materials 2025 held at Singapore.

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