Silver-Catalyzed CO2 Electroreduction

Silver-Catalyzed CO2 Electroreduction

Author: Angewandte Chemie International Edition

The greenhouse gas CO2 can be electrochemically reduced to give valuable products, using electricity sourced from renewable energies. Silver-based catalysts are highly active in CO2 electroreduction, but require a high overpotential, which makes the process economically impractical.

Beatriz Roldan Cuenya, Ruhr University Bochum and Fritz-Haber Institute of the Max Planck Society, Berlin, both Germany, Jan Rossmeisl, University of Copenhagen, Denmark, and colleagues have prepared silver foils with a low overpotential and a maximum CO Faradaic efficiency of 90 % at –0.6 V vs. a reversible hydrogen electrode (RHE).

The catalysts were pretreated with low-pressure O2 plasma to increase the roughness of the surface as well as the number of subsurface oxygen species. The team used scanning electron microscopy (SEM) and X-ray spectroscopy techniques to correlate improvements in catalytic performance with surface defects.

Density functional theory (DFT) calculations revealed that electric field effects on the defect-rich surface promote the reduction of CO2 to CO at low overpotentials. The study identifies surface defect sites as a key factor in lowering the thermodynamic barrier of the electrochemical reduction of CO2 to CO.


 

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