Getting the genie out of the lab flask: Molecular electrocatalysts for application relevant CO2 electrolysis – An introductory review

Since several decades the electrochemical CO 2 reduction is investigated as a promising approach to sustainably produce carbon-based feedstocks for the chemical industry. Within this field especially transition metal complexes have been broadly investigated but are commonly applied in homogenous catalysis, which is not suitable for scaled up systems with industrial relevance. During the last years the employment of these molecular catalysts within gas diffusion electrodes in scalable electrolyzers, such as flow cells and zero-gap cells/membrane electrode assemblies, has emerged. Within this review a detailed introduction into the relevant electrolyzer types, alongside all relevant components thereof is given, followed by a summary of the results achieved so far within this field of research to highlight this promising compound class for scalable CO 2 electrolysis. • Provides a comprehensive overview of scalable electrolyzer concepts for CO₂ electroreduction. • Focuses on the integration of molecular transition metal complexes in gas diffusion electrodes. • Discusses the role of catalyst–electrode–membrane interactions in device performance. • Summarizes key advances in flow cell and membrane electrode assembly (MEA) architectures. • Highlights the potential of molecular catalysts for industrially relevant CO₂ valorization.