Electrocatalysts are essential in facilitating energy conversion reactions, such as hydrogen evolving reaction (HER) or carbon dioxide reduction reaction (CRR). To improve the performance of electrocatalysts, identifying a key descriptor that is highly correlated to electrocatalytic performance and understanding the reaction mechanism play a significant role.  Electrochemical methods, such as cyclic voltammetry, are widely used to evaluate the performances of electrocatalysts and probe reaction mechanisms. However, the determination of rate constants from voltammograms is not trivial and generally involved with electrokinetic modelling and analysis. They are particularly challenging for multi-electron and multi-step redox reactions. Recently, a simple method developed by us, based on the earlier method developed by Savéant and Costentin, offers a reliable approach to determine the rate constants for multi-electron redox reactions.

     Based on these electrokinetic models developed, we further analyse electrocatalytic mechanisms of molecular catalysts that mediate the HER, CRR and oxygen reduction reaction. The effects of the second coordination sphere and beyond on those reactions were investigated. In addition, we also constructed kinetic models for heterogeneous film systems (such as metal-organic framework) to understand the interplay among charge transport, substrate diffusion and chemical catalysis inside a film. These models provide important clues to probe how these factors individually or collectively affect the overall electrocatalytic performance. The common strategies for optimising an electrocatalyst derived from these analyses will be shared in this talk.