Facet-Dependent Catalytic Selectivity for Electrochemical Reduction of CO on Copper

The electrochemical reduction of CO on copper catalysts has garnered significant attention for its potential in synthesizing valuable chemicals like formic acid and ethylene. However, high selectivity and efficiency remain challenging due to the complex interplay of various reaction pathways and surface morphology. This study employs potential-dependent density functional theory (DFT) and microkinetic modeling to investigate the facet-dependent catalytic selectivity of the CO reduction (COR) on copper. We analyzed metal active sites across facets (100), (111), (211), (310), and (511), computing the energetics of COR adsorbates at the standard hydrogen electrode (SHE) scale. Initial assessments examined the effects of applied voltage and the electrical double layer on adsorption energetics, followed by evaluations of selectivity towards C₁₊ and C₂₊ products at varying potentials. Our results indicate that while facet (111) is the highly active, favoring C₁ products, facets (100), (310), and (511) demonstrate enhanced selectivity towards C₂₊ products. Conversely, facet (211) shows notable activity but lacks selectivity towards C₂₊ products, underscoring the diverse catalytic behaviors across different facet types. Comparisons with experimental data confirm that our findings accurately represent the unique properties of each facet. This research highlights the critical role of copper surface morphology in influencing the microkinetics and product selectivity in CO reduction, paving the way for advanced catalyst design.