Ion‐Enhanced Conversion of CO2 into Formate on Porous Dendritic Bismuth Electrodes with High Efficiency and Durability

Facile synthesis of efficient electrocatalysts that can selectively convert CO2 to value‐added chemicals remains a challenge. Herein, the electrochemical synthesis of porous Bi dendrite electrodes and details of their activity toward CO2 conversion to formate in aqueous solutions of bicarbonate are...

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Bibliographic Details
Published in:ChemSusChem 2020-02, Vol.13 (4), p.698-706
Main Authors: Piao, Guangxia, Yoon, Sun Hee, Han, Dong Suk, Park, Hyunwoong
Format: Article
Language:English
Subjects:
Aqueous solutions
Bicarbonates
Bismuth
Carbon dioxide
carbon dioxide fixation
Cesium
Chemical synthesis
Dendritic structure
Efficiency
electrocatalysis
Electrocatalysts
electrochemistry
Electrodes
Energy conversion efficiency
Halides
Organic chemistry
porous materials
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Summary:Facile synthesis of efficient electrocatalysts that can selectively convert CO2 to value‐added chemicals remains a challenge. Herein, the electrochemical synthesis of porous Bi dendrite electrodes and details of their activity toward CO2 conversion to formate in aqueous solutions of bicarbonate are presented. The as‐synthesized multilayered, porous, dendritic Bi electrodes exhibit a faradaic efficiency (FE) of approximately 100 % for formate production. Added halides and cations significantly influence the steady‐state partial current density for formate production JFM (Cl−>Br−≈I−; Cs+>K+>Li+). DFT calculations revealed that the reaction pathway involving the species *OCOH occurs predominantly and the presence of both Cs+ and Cl− makes the overall reaction more spontaneous. Photovoltaic‐cell‐assisted electrocatalysis produced formate with an FE of approximately 95 % (JFM≈10 mA cm−2) at an overall solar conversion efficiency of approximately 8.5 %. The Bi electrodes maintain their activity for 360 h without a change in the surface states. Bi the way: Porous Bi dendrite electrodes synthesized by a rapid, facile electrodeposition process show higher CO2 conversion activity than planar Bi electrodes, owing to a larger surface area and lower charge‐transfer resistance. A photovoltaic‐cell‐coupled IrO2 anode/porous Bi cathode pair produces O2 and formate with faradaic efficiencies of approximately 95 % and overall solar‐to‐formate conversion efficiency of approximately 8.5 %.
ISSN:1864-5631
1864-564X
DOI:10.1002/cssc.201902581