Toward Unifying the Mechanistic Concepts in Electrochemical CO2 Reduction from an Integrated Material Design and Catalytic Perspective

Electrocatalytic CO2 reduction (eCO2RR) is one of the avenues with most potential toward achieving sustainable energy economy and global climate change targets by harvesting renewable energy into value-added fuels and chemicals. From an industrial standpoint, eCO2RR provides specific advantages over thermochemical and photochemical pathways in terms of much broader product scope, high product specificity, and easy adaptability to the renewable electricity infrastructure. However, unlike water electrolyzers, the lack of suitable cathode materials for eCO2RR impedes its commercialization due to material design challenges. The current state-of-the-art catalysts in eCO2RR suffer largely from low reaction rates, insufficient C2+ product selectivity, high overpotentials, and industrial-scale stability. Overcoming the scientific and applied technical hurdles for commercial realization demands a holistic integration of catalytic designs, deep mechanistic understanding, and efficient process engineering. Special emphasis on mechanistic understanding and performance outcome is sought to guide the future design of eCO2RR catalysts that can play a significant role in closing the anthropogenic carbon loop. This article provides an integrative approach to understand principles of robust eCO2RR catalyst design superimposed with underlying mechanistic projections which strongly depend on experimental conditions viz. choice of electrolyte, reactor and membrane design, pH of the solvent, and partial pressure of the CO2.