Catalytic Particle Size Effects in the Catalytic CO₂ Electroreduction on Cu

A combined experimental and computational study of catalytic particle size effects during CO₂ electroreduction on size-controlled Cu nanoparticles is presented. Cu nanoparticle catalysts in the 2 – 15 nm mean size range were prepared, and their catalytic activity and selectivity during CO₂ electroreduction were analyzed and compared to bulk Cu electrode. An increase in the catalytic activity as well as the H₂ and CO selectivity was observed with decreasing Cu particle size, in particular for particles below around 2 nm. Hydrocarbon (methane and ethylene) selectivity was increasingly suppressed with smaller particle size. A spherical Cu particle model was used to analyze the size dependence of the surface atomic coordination, which was correlated to experimental results.