The SOLDAC project has recently come to an end. The main goal was to demonstrate the production of carbon-neutral multi-carbon products from the air, through an independent, off-grid, decentralized and market-competitive process powered by solar energy. At the end of the project, SolDAC has successfully demonstrated that capturing CO₂ into chemicals like ethylene and ethanol is possible. Its three-unit system (direct air capture, full spectrum solar, and photo-electrochemical conversion) addresses environmental challenges and creates new economic opportunities in the chemical industry.

IREC’s contribution, led by Andrés Alberto García, together with Sebastián Murcia, Nina Carretero and Martí Biset from the Sustainable Fuels group, focused on developing an optimized photoelectrochemical (PEC) device for the conversion of CO₂ into ethylene and other multi-carbon (C₂₊) products. Novel catalysts and electrode architectures were designed for both the cathode and the photoanode. Insights gained into the role of catalyst/additive heterojunctions enabled achieving combined Faradaic efficiencies towards C₂₊ products of ≥ 90%.

In parallel, significant efforts were dedicated to the design and scale-up of the PEC cell, including the optimization of membrane selection, cell potential, and flow distribution. These developments were key to ensuring stable performance and efficient mass transport in the final prototype configuration.

An optimized cell design led to the construction of a 100 cm² prototype which was integrated and tested under concentrated solar radiation provided by the Full Spectrum Solar system (University of Lleida). Coupling tests validated the feasibility of bias-free electrochemical synthesis of C₂₊ products under real conditions.

The SOLDAC consortium is formed by 6 European and 2 associated partners, including Comet Global Innovation S.L. (leader), IREC, Consiglio Nazionale delle Ricerche (CNR), among others.

You can watch the final overall video at: https://www.youtube.com/watch?v=lck8RmN5D5g

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