The electrochemical conversion of CO₂ into carbon-based fuels and valuable feedstocks by renewable electricity is an attractive strategy for carbon neutrality. CO is the key component of syngas, a mixture of CO and H₂ that can be directly converted into various value-added chemicals via well-developed industrial processes such as Fischer-Tropsch synthesis, methanol synthesis, etc. Therefore, CO₂ electroreduction to CO is considered to be one of the most promising routes to obtain cost-competitive products.

However, due to the low solubility and diffusion coefficient of CO₂ in aqueous electrolytes, it remains a challenge to possess a large current density, a high faradaic efficiency and excellent stability for practical applications of CO₂ utilization.

Motivated by such a challenge, a research team led by Profs. CHEN Wei and WEI Wei from the Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences reported a facile tactic that enables exceedingly efficient CO₂ electroreduction to CO by virtue of low-coordination chloride ion (Cl^-) adsorption on a silver hollow fiber (Ag HF) electrode.

The results were published in Angew. Chem. Int. Ed. on September 3.

On the basis of the high efficient electroreduction CO₂ to CO over silver hollow fiber (Ag HF) electrode, the research team further introduced chloride ions into the electrode solution, by means of specific adsorption of chloride ions, the electronic structure of the electrode surface was functionally regulated to inhibit the side reaction of hydrogen evolution (HER).

This work provides a new strategy for further developing electrocatalytic CO₂ systems with high current density, high selectivity and high stability in CO₂utilization and chlor-alkali industry.

Schematic diagram and electrocatalytic performance of efficient CO₂ reduction over silver hollow fiber electrode with chloride ion adsorption (Image by SARI)