Geopolymer Based Electrodes as New Class of Material for Electrochemical CO₂ Reduction

To achieve a successful transition to a sustainable carbon and energy management, it is essential to both reduce CO₂ emissions and develop new technologies that utilize CO₂ as a starting substrate. In this study, we demonstrate for the first‐time the functionalization of geopolymer binder (GP) with Sn for electrochemical CO₂ reduction (eCO2RR) to formate. By substituting cement with Sn‐GP, we have merged CO₂ utilisation and emission reduction. Using a simple mixing procedure, we were able to obtain a pourable mortar containing 5 vol. % Sn‐powder. After hardening, the Sn‐GP electrodes were characterized for their mechanical and CO₂ electrolysis performance. In 10 h electrolyses, formate concentrations were as high as 22.7±0.9 mmol L⁻¹ with a corresponding current efficiency of 14.0±0.5 % at a current density of 20 mA cm⁻². Our study demonstrates the successful design of GP‐electrodes as a new class of hybrid materials that connect eCO2RR and construction materials.

Geoploymers for CO₂ reduction: Geoploymers offer great potential for reducing CO₂ emissions in the construction sector by replacing ordinary cement. Here, we successfully functionalized a geopolymer with tin and applied the hybrid material as an electrode for CO₂ electrolysis. The results show current efficiencies of up to 14 % for formate production.