Microkinetic studies for mechanism interpretation in electrocatalytic CO and CO2 reduction: current and perspective

Abstract

Microkinetic analysis can establish the relationship between the atomic-level reaction mechanism and macroscopic observables, such as reaction rates, product selectivity, Tafel slope, reaction order, isotopic effect, and apparent activation energy, at given operating conditions. This relationship is essential in the rational design of electrocatalysts and reactor configurations. In recent years, microkinetic analysis, particularly Tafel and reaction order analysis, has seen significant advancements in its application for interpreting reaction mechanisms in electrocatalytic CO and CO₂ reduction. This review summarizes the progress in understanding the complex kinetic processes through theoretical microkinetic simulation modeling and experimental measurements. However, the reaction mechanisms derived from microkinetic analysis are disputed, complicating efforts to design electrocatalysts. This review analyzes the discrepancies in the literature and elucidates deeper insights into experimental discrepancies. The importance of local reaction environments in the intrinsic kinetic behavior of electrocatalysts is highlighted. The report also discusses the challenges and limitations of microkinetic analysis. Finally, the review suggests some perspectives on future investigations. Overall, this review is expected to provide new insights, critical interpretation, and guidance for the future development of microkinetic measurements and analysis.