(509ae) Decorating Copper Nanostructures with Atomic Palladium and Silver Species to Regulate Product Selectivity in CO2 Electroreduction

Utilizing the precise-functional catalytic systems, it is possible to control the CO₂ electroreduction process to value-added specific products like methane, ethylene, methanol, formic acid. In this work, we report our progress of developing single-atom alloy catalysts, an emerging group of materials stemmed from vacuum and thermal reaction studies, to prove the promises in electrocatalytic reactions. As the most versatile catalytic metal for CO₂ electroreduction, copper alone often directs the reactions toward the cross-coupling of weakly bound -CO intermediates, resulting in heterogeneity in products. In order to obtain alcohol and other C-Oxygenate products, an improved catalytic surface should stabilize the isolated and protonated CO i.e., CHO* to drive up both catalytic activity and selectivity. Herein, we prepare different Cu crystal with exclusive facets (<111> and <100>), and then we alloy those more noble metal atoms as the atomically dispersed secondary site on copper nanostructures (cubes, tetrahedra and truncated octahedra) to facilitate those critical elementary reaction steps favoring alcohol and other C-Oxygenate formation. We use galvanic displacement reaction to obtain Pd and Ag single atom alloys with Cu (varying viscosity and reaction kinetics at ppm level). The electroreduction studies of CO₂ with this family of atomic alloy catalysts indicate interesting phenomenon in line with our hypothesis. As expected, the Cu <111> and <100> facets have important role to play in electrochemical activity. Moreover, the nature of the alloy metals has a profound effect on CO₂ electroreduction and product distribution. While Pd is more efficient in improving the current density, Ag helps in tuning the product towards C-Oxygenate. Characterization results, particularly under reaction conditions, such as ATR-SEIRAS, HAADF-STEM and XAS will be used to interrogate the atomic structure of these new catalysts. With these analyses, we will plan to propose mechanistic model to explain the catalytic activity, thus helping in further fundamental understanding.