Researchers propose novel method to enhance electrocatalytic conversion of carbon dioxide

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 novel method that enables efficient CO₂ electroreduction to CO by virtue of low-coordination chloride ion adsorption on a silver hollow fiber electrode.

The results were published in Angewandte Chemie International Edition.

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. Therefore, CO₂ electroreduction to CO is 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 large current density, high faradaic efficiency and excellent stability for practical applications of CO₂ utilization.

In this study, on the basis of the highly efficient electroreduction CO₂ to CO over silver hollow fiber 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.

The low-coordination chloride ion adsorption on a silver hollow fiber electrode reduced CO₂ to CO at a stable (>150 h) ampere-level current density (1 A·cm^-2) and with a high CO faradaic efficiency (>92%).

Electrochemical experiments demonstrated that the high concentration Cl- in the electrolyte could be low-coordination adsorbed onto the surface of silver hollow fibers. This not only hinders the occurrence of the hydrogen evolution reaction, but also optimizes the kinetics of CO₂ reduction to CO, leading to a better eCO₂RR performance, even at the ampere-level current density.

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