Effects of Iron Species on Low Temperature CO₂ Electrolyzers

Electrochemical energy conversion devices are considered key in reducing CO₂ emissions and significant efforts are being applied to accelerate device development. Unlike other technologies, low temperature electrolyzers have the ability to directly convert CO₂ into a range of value-added chemicals. To make them commercially viable, however, device efficiency and durability must be increased. Although their design is similar to more mature water electrolyzers and fuel cells, new cell concepts and components are needed. Due to the complexity of the system, singular component optimization is common. As a result, the component interplay is often overlooked. The influence of Fe-species clearly shows that the cell must be considered holistically during optimization, to avoid future issues due to component interference or cross-contamination. Fe-impurities are ubiquitous, and their influence on single components is well-researched. The activity of non-noble anodes has been increased through the deliberate addition of iron. At the same time, however, Fe-species accelerate cathode and membrane degradation. Here, we interpret literature on single components to gain an understanding of how Fe-species influence low temperature CO₂ electrolyzers holistically. The role of Fe-species serves to highlight the need for considerations regarding component interplay in general.