Effect of Particle Shape and Electrolyte Cation on CO Adsorption to Copper Oxide Nanoparticle Electrocatalysts

Cu2O-derived nanoparticles are efficient catalysts for the electrochemical conversion of CO and CO2 to multi-carbon products. Generation of multi-carbon products requires dimerization of adsorbed CO, which is accelerated when the coverage of CO is high. The electrolyte cation and the initially exposed crystal plane of the catalyst both affect the reaction rate, but the relation between these effects and CO coverage is unclear, especially given the surface reconstruction that occurs during reduction reactions on Cu2O. We prepared a series of shape-controlled Cu2O nanoparticles with similar sizes but different initially exposed crystal planes (cubes (100), octahedra (111), and dodecahedra (110)), and we used the IR absorption bands detected in-situ to compare the potential-dependent CO coverage on each of the nanomaterials in CO-saturated 0.1 M NaHCO3 and CsHCO3 during cyclic voltammetry. After correcting for the shape of the particle, there was less than 20% difference in the coverage of adsorbed CO on the...