(66c) Electrochemical CO2 Reduction over Cuag Bimetallic Electrodes and Well-Defined Surface Alloys with Enhanced Oxygenate Selectivity
- Conference: AIChE Annual Meeting
- Year: 2017
- Proceeding: 2017 Annual Meeting
- Group: Catalysis and Reaction Engineering Division
- Time: Monday, October 30, 2017 - 8:37am-8:55am
Herein we report our investigations of electrochemical CO2 reduction over CuAg bimetallic electrodes and well-defined surface alloys, which we have found to exhibit an enhanced activity for the evolution of products derived from CO relative to H2 compared to pure Cu. Furthermore, we have found that these electrocatalysts display an unusually high selectivity for the formation of carbonyl-containing compounds, such as acetaldehyde. While this bimetallic system was investigated on the hypothesis that CO spillover from phase-segregated domains of Ag to Cu would increase the rate of C-C coupling, further characterization by photoelectron spectroscopy and electrochemical cycling led to a very different conclusion. The revised hypothesis was confirmed by synthesizing well-defined Cu+Ag surface alloys, which reproduced the activity and selectivity trends observed over the bimetallic electrodes. The results are explained in terms of an observable shift in the electronic properties of Cu and the resulting impact that these modifications have on the adsorption energies of key reaction intermediates.