From Theory to Practice: A Critical and Comparative Assessment of Tafel Slope Analysis Techniques in Electrocatalytic Water Splitting

Water splitting for clean hydrogen production is gaining popularity, driving researchers to develop efficient electrocatalysts with minimal energy input, reduced overpotentials, lower Tafel slopes, and enhanced stability. The Tafel slope is an important kinetic parameter to assess an electrocatalyst's performance. Hence, an accurate determination of the Tafel slope experimentally using appropriate techniques, along with knowledge of multielectron transfer reactions' kinetics, is of utmost importance. For such reactions, identifying whether the rate-determining step involves an electron transfer or chemical transformation is a key factor. The Tafel slope provides insight into this, revealing the exact equilibrium and mechanism of the reaction. This Perspective explores the theoretical background of the Tafel slope and current experimental techniques for its accurate determination. It discusses the pros and cons of each technique, providing step-by-step guidance for precise Tafel slope calculation, which is essential for assessing electrocatalyst performance in water splitting reactions.