The electrochemical conversion and valorization of CO₂ into value-added products offer a highly efficient and promising alternative to reduce CO₂ emissions from industrial sources of hard-to- abate sectors such as cement industry among others. This process involves utilizing CO₂ as feedstock for chemical production, with a focus on closing industrial carbon loops and transforming CO₂ into useful products such as formic acid or formate, methanol, or ethylene. Although CO₂ electroreduction has been extensively studied at lab scale with low Technology Readiness Level (TRL), efforts are still underway to develop efficient reactor configurations capable of successful technology scaling.

The EU-funded CAPTUS project aims to demonstrate sustainable and cost-effective pathways to produce renewable energy carriers in energy intensive industries by valorizing industrial carbon emissions and integrating renewable energy sources. The project will demonstrate a CO₂ valorization pilot to produce formic acid/formate including carbon capture and utilization technologies, both coupled for an efficient and selective electrochemical conversion of CO₂ in continuous operation.

This work aims to design and construct functional prototype of a CO2 electrolyzer demonstrator as a first step towards implementing CO2 electroreduction to formic acid on an industrial scale. The electrolyzer (180x180 mm) comprises several components: i) outer closure plates made of stainless steel, ii) an external reactor structure constructed from polypropylene, iii) internal spacers composed of Viton, and iv) titanium current collectors. In the anode compartment, an iridium mixed oxide plate acts as the counter electrode for the water oxidation reaction. As for the cathode, a Gas Diffusion Electrode (GDE), with an active geometric area of 100 cm2 is employed. The electrochemical reactor can operate in both Liquid-Liquid (L-L) and Liquid-Gas (L-G) configurations.

An advanced upscaled reactor of 1000 cm² to convert the almost pure CO₂ stream derived from a CSAR unit (ca. 98%) will be developed, optimized and demonstrated at GCPV cement plant facilities in Mataporquera (Cantabria, Spain).The pilot of this technology, engineered and constructed by APRIA, will  cover the study of the effect of the flue-gas on the behaviour of CO₂ reduction, and the integration of all the necessary steps to transform CO₂ into formic acid/formate at industrial scale enabling continuous and efficient electrochemical CO₂ conversion.