The electrode reduces CO2 to CO with CO2 conversions exceeding 54% at a high space velocity of 31,000 mL gcat-1·h-1 under ambient conditions, maintaining stable large current densities (~1.26 A·cm-2) and high CO faradaic efficiencies (~93%).
The results were published in Nature Communications on June 2.
The electrochemical conversion of CO2 into carbon-based fuels and valuable feedstocks by renewable electricity is an attractive strategy for CO2 abatement and renewable energy consumption that can help achieve the goal of 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 one of the most promising means of obtaining cost-competitive products. However, highly efficient CO2 conversion with high space velocity under mild conditions remains a challenge.
The hollow-fiber electrode with hierarchical micro/nanostructures in this study is composed of only metallic silver (Ag) for electroreducing CO2 to CO. Such a porous, hollow-fiber Ag electrode acting as a CO2 disperser not only enhances three-phase interface reactions but also guides mass transfers during electrolysis.
Electrochemical results and time-resolved operando Raman spectra demonstrate that enhanced three-phase interface reactions and oriented mass transfers synergistically boost CO production.
Schematic illustration of hollow fiber electrode for boosting CO2 reduction to CO.
This result provides new opportunities for heightening three-phase interface reactions and mass transfer kinetics simultaneously. In addition, it demonstrates that the micro/nanostructured Ag hollow fiber can be an ideal industrial electrode with excellent durability, representing an encouraging advancement in CO2 electroreduction that may lead to scalable applications.
Read the original article on Chinese Academy of Sciences (CAS).