Enhanced electrochemical carbon dioxide reduction in membrane electrode assemblies with acidic electrolytes through a silicate buffer layer

Abstract

The electrochemical reduction of CO₂ holds considerable promise in combating global climate change while yielding valuable chemical commodities. Membrane electrode assemblies operating within acidic electrolyte have exhibited noteworthy advancements in CO₂ utilization efficiency, albeit encountering formidable competition from the hydrogen evolution reaction. In our investigation, we introduced a silicate buffer layer, which yielded exceptional outcomes even using strong acid electrolyte. Notably, our approach yielded a CO Faradic efficiency of 90% and reached a substantial current density of 400 mA cm^–2. Furthermore, our system displayed remarkable stability over a 12-hour duration, and achieved a high single-pass-conversion efficiency of 67%. Leveraging in-situ Raman analysis, we attributed these performance enhancements to the augmented CO₂ adsorption and localized alkaline environment facilitated by the incorporation of the silicate buffer layer. We think the addition of buffer layer to adjust the microenvironment is essential to achieve high performance and keep stable in acid condition.