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O: Fachverband Oberflächenphysik

O 72: Solid-Liquid Interfaces: Reactions and Electrochemistry

O 72.3: Poster

Mittwoch, 9. März 2016, 18:15–20:30, Poster A

Achieving selective electrocatalytic activity for CO2 reduction using highly porous Cu black catalysts — •Abhijit Dutta, Motiar Rahaman, Miklos Mohos, Nicola Christian Ludi, and Peter Broekmann — Department of Chemistry and Biochemistry, University of Bern Freiestrasse 3 CH 3012 Bern Switzerland

The selective electroreduction of carbon dioxide to ethane and carbon monoxide on porous Cu-black catalysts has been investigated at various electrochemical potentials in aqueous 0.5 M NaHCO3 solution. The evolution of hydrogen gas at an electrode surface plays a significant role to form this novel porous architecture during the electrodeposition of copper, particularly when a high current density is maintained. The hydrogen gas evolution inhibits electrodeposition of copper directly onto the cathode by temporarily preventing contact between the copper cathode and the electrolyte. Ultimately, a thin film of electrolyte surrounding hydrogen bubble comes into contact with the cathode, which completes the EC circuit and permits for electrodeposition of copper black. This porous morphology remains alike even after 1 h electrolysis at -1.0 V vs RHE. The Cu black catalyst exhibited the best selectivity for CO and ethane at -0.50V and -0.70V vs RHE with faradaic efficiencies of 40% and 37% respectively. Furthermore, the total FE of these two products is almost 75 to 80% at moderately cathodic potential range. Understanding the structural morphology of Cu black and the selectivity of products distribution could be valuable for the further development of advanced electro-catalytic materials for carbon di-oxide reduction.