Enhanced Carbon Dioxide Electroreduction to Carbon Monoxide over Defect-Rich Plasma-Activated Silver Catalysts

Hemma Mistry, Yong-Wook Choi, Alexander Bagger, Fabian Scholten, Cecile S. Bonifacio,
Ilya Sinev, Nuria J. Divins, Ioannis Zegkinoglou, Hyo Sang Jeon, Kim Kisslinger, Eric A. Stach, Judith C. Yang, Jan Rossmeisl,* and Beatriz Roldan Cuenya*

Manuscript published in Angew. Chem. Int. Ed. 2017, 56, 1 – 6
DOI: https://doi.org/10.1002/anie.201704613


In this work, a plasma oxidation pre-treatment of silver foil enhances the catalytically active sites, which dramatically lowers the overpotential and increases the activity of CO 2 electroreduction to CO. At 0.6 V versus RHE more than 90 % Faradaic efficiency towards CO was achieved on a pre-oxidized silver foil. To understand this we calculated a number of Ag defect structures, including Cu and Au 111 facet and step structures to construct a volcano-like plot. This shows that the not even defects of Ag should be able to reduce CO2 to CO, however by applying an electrical field to the calculations, to simulate the electrochemical environment, it seems that defected Ag site should be able to reduce CO2 towards CO at such low overpotential. Due to the use of the oxygen precusor, to produce such rough Ag samples, also an Ag2O and Ag (111) facet with subsurface oxygen, is included in the vulcano plot. However, these Ag + oxygen structrues are 1) not stable at reducing potential and 2) the strutures bind CO* to strong and should then allow further reduction of CO*. Thus, Ag + oxygen structures is unlikely to be the origin of the low overpotential. 

The Database

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Key-value pairs: Description

Given and used in python scripts, but also listed below here.

Key words for database:

facet 'Ag111', 'Ag211', 'Ag211K', 'Ag211A', 'Ag111A', 'Cu111', 'Cu211', 'Au111', 'Au211', 'Ag111_O', 'Ag2O' ads:  'slab', 'CO','COOH'
field: '0', '2', '4', '6'

Volcano plot of CO2 reduction to CO.

The free energy on the weak-binding side is defined as the CO2 + H+ + e- -> COOH*. On the strong-binding side, the potential-independent CO -> CO step is the limiting factor.