Combined Kinetic Modeling of NiFe-LDH Electrocatalyst for Oxygen Evolution Reaction

Abstract The oxygen evolution reaction (OER) is the core anodic half-reaction of water electrolysis for sustainable hydrogen production. Nickel–iron layered double hydroxides (NiFe-LDHs) are emerging as benchmark OER electrocatalysts owing to their exceptional catalytic activity, yet a systematic understanding of their intrinsic OER kinetic mechanisms remains elusive. Herein, we systematically investigate the OER kinetic behaviors of NiFe-LDH electrocatalysts via a newly developed physically constrained kinetic fitting strategy. Two kinetic models, describing intrinsic reaction kinetics and coupled mass-transfer kinetics respectively, are established to precisely replicate experimental kinetic characteristics. Key kinetic parameters that cannot be experimentally measured, including the potential-dependent coverage of critical intermediates (OH*, O*, and OOH*) and rate constants of elementary reaction steps, are quantitatively extracted. This work develops a reliable methodology to decode microscopic kinetic characteristics from macroscopic electrochemical measurements. The mechanistic insights not only clarify experimental phenomena but also provide predictive guidance for the targeted design of high-efficiency OER electrocatalysts, offering significant theoretical and practical implications for the advancement of water-splitting electrocatalysis.