Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 53: Focus Session: Electrocatalytic Energy Harvesting and Conversion
O 53.5: Topical Talk
Mittwoch, 9. März 2016, 12:45–13:15, S052
CO2 Electroreduction over Cu and Au Nanostructured Catalysts: Size, Oxidation State and Interparticle Distance Effects — Hemma Mistry1,2, Rulle Reske3, Farzad Behafarid2, Ana Sofia Varela3, Peter Strasser3, and •Beatriz Roldan Cuenya1 — 1Department of Physics, Ruhr-University Bochum, 44708 Bochum, Germany — 2Department of Physics, University of Central Florida, Orlando FL 32816, USA — 3Department of Chemistry, Chemical Engineering Division, Technical University Berlin, 10623 Berlin, Germany
The electrocatalytic reduction of CO2 to industrial chemicals and fuels is a promising pathway to sustainable electrical energy storage and to an artificial carbon cycle, but is currently hindered by the low energy efficiency and activity displayed by traditional electrode materials. The structure-dependent catalytic activity of Cu and Au nanoparticle (NP) catalysts for the electroreduction of CO2 is reported here. NPs with well-defined size and interparticle distance were synthesized, and their activity and selectivity measured. A drastic increase in current density was observed with decreasing Au NP size, along with a decrease in selectivity towards CO. Cu NP catalysts also displayed a significant increase in the catalytic activity and selectivity for H2 and CO with decreasing NP size, while methane and ethylene selectivity was increasingly suppressed. The size dependent trends observed can be rationalized by the increased population of low-coordinated surface sites on smaller NPs. The selectivity of Cu NP catalysts could be tuned by varying the interparticle distance due to mass transport phenomena such as reactant diffusion and readsorption of intermediates.