The conversion of CO₂ into high value-added mono- or multi-carbon products represents a particularly promising area of research for achieving negative CO₂ emissions whilst, at the same time, utilising CO₂ as a carbon-based raw material. The CO₂ reduction reaction (CO₂RR), powered by electricity from renewable sources, offers an effective solution for utilising CO₂. CO₂RR reactors based on gas diffusion electrodes (GDEs) significantly increase current density to levels relevant for commercial applications, thanks to thinner mass-transfer layers that overcome the diffusion limitations typical of aqueous systems. However, achieving highly stable GDEs remains a challenge, particularly under high current density operating conditions, due to electrolyte flooding resulting from the loss of hydrophobicity. Consequently, the GDE is the key element for the technological feasibility of CO₂RR, but improving its performance is essential. What distinguishes this proposal from previous research is the aim to demonstrate an innovative approach to reinforcing the structure of copper-based GDEs through the formation of bimetallic structures that exploit the tandem effect without the use of precious metals, thereby improving selectivity towards two-carbon (C₂) products. An improvement in performance and selectivity towards C₂ products is anticipated thanks to the formation, for the first time, of Cu-W (copper-tungsten) heterostructures free of noble metals. These structures generate heteroatomic reaction sites between tungsten (W) atoms – characterised by a high affinity for oxygen – and copper (Cu) atoms, thereby reducing the binding energy of adsorbed carbon monoxide (CO). At the same time, electrode flooding is minimised thanks to the hydrophobic surface topology achieved. This particular surface topology endows the GDE with a high surface area and adequate hydrophobicity, enabling the formation of a stable interface between the electrode and the electrolyte. This configuration not only allows a greater quantity of CO₂ to be trapped along the hierarchical Cu-W surface—which acts as a set of tandem active sites—but also effectively prevents electrolyte flooding even at high operating rates. 

The expected outcomes of the FOTOCER project contribute to the development of cutting-edge industrial technologies for the conversion of CO₂ into useful C₂+ products, which are essential for achieving the European Union’s environmental objectives whilst ensuring sustainable costs for industrial-scale upscaling.