Copper Nanocubes for CO 2 Reduction in Gas Diffusion Electrodes.

Electroreduction of CO ₂ represents a promising solution for addressing the global challenges in energy and sustainability. This reaction is highly sensitive to the surface structure of electrocatalysts and the local electrochemical environment. We have investigated the effect of Cu nanoparticle shape on the electrocatalysis of CO ₂ reduction by using gas-diffusion electrodes (GDEs) and flowing alkaline catholytes. Cu nanocubes of ∼70 nm in edge length are synthesized with {100} facets preferentially exposed on the surface. They are demonstrated to possess substantially enhanced catalytic activity and selectivity for CO ₂ reduction, compared to Cu nanospheres of similar particle sizes. The electrocatalytic performance was further found to be dependent on the concentration of electrolyte (KOH). The Cu nanocubes reach a Faradaic efficiency of 60% and a partial current density of 144 mA/cm ² toward ethylene (C ₂ H ₄ ) production, with the catalytic enhancement being attributable to a combination of surface structure and electrolyte alkalinity effects.