(651b) Highly Efficient C2+ Alcohols Electrosynthesis Enabled By Bi-Metal Cu-Based Alloys

Selective electrocatalytic reduction of CO₂ to value-added chemicals and fuels using renewable electricity is an attractive approach to fulfill the global energy demand of modern society and close the anthropogenic carbon cycle. Depending on the electrocatalyst utilized, a variety of products can be produced in the CO₂ reduction reaction including CO and formic acid, as well as C₂₊ products such as ethylene and alcohols. Although, many advances have been made in the simplest two-electron reduction of CO₂ to CO or formic acid, the production of C₂₊ alcohols still suffers from poor selectivity and high overpotential resulting in a low energy efficient process.

Given the fact that the developed catalysts can effectively produce CO ­–identified to be a key intermediate for C₂₊ products– further reducing CO to C₂₊ alcohols in a tandem design can potentially enhance the selectivity and efficiency of the process.

We are presenting nanostructured Bi-metal Cu-based alloys (Cu-BMA) that catalyze CO₂ in a two-step sequential reaction to produce C₂₊ products with remarkable activity and selectivity. The electrocatalytic performance of the Cu-BMA was studied in a two-compartment cell using 1M KOH electrolyte. The results show an overall current density of about -200 mA/cm², and a C₂₊ alcohols formation FE of about 63±2% (n-propanol 41% and ethanol 22%) at a potential of -0.5 V vs. RHE. Furthermore, the selectivity analyses at the potential of -0.5 V vs. RHE indicate that the Cu-BMA produces acetate and ethylene with FEs of 15±2 and 21±4%, respectively. We have performed different characterizations, such as XRD, XPS, HRTEM, and EIS to gain an understanding of structural, physicochemical, and electronic properties of Cu-BMAs and identify the key factors that affect their electrocatalytic performance. Moreover, in-situ Raman spectroscopy has been conducted at different potentials to investigate mechanism of the CO reduction reaction on the Cu-BMA catalysts.