Electrochemical CO₂Reduction over Bimetallic Au-Sn Thin Films: Comparing Activity and Selectivity against Morphological, Compositional, and Electronic Differences

Carbon dioxide can be electrochemically converted into feedstocks for many industrial processes, such as the manufacturing of synthetic fuels and chemicals. This work focuses on the structure-functionality relationship between Au, Sn, and bimetallic AuSn catalysts and their CO2 reduction performance in an H-Cell at varying current densities. X-Ray diffraction (XRD), X-ray photoemission spectroscopy (XPS), and atomic force microscopy (AFM) were used to determine the crystal structure, surface morphology, and composition of compositionally variant bimetallic thin films of Au-Sn before and after electrolysis. The electrochemical activity for each bimetallic film was measured in terms of electrode current and product selectivity as a function of applied current density and catalyst composition. The results of this work show that not all combinations of metals for CO2 reduction can improve catalyst activity toward a desired product and that a detailed material characterization can help in drawing structure-functionality relationships between a catalyst and its activity.