Pressure and bias dependence of the rate-limiting steps of the oxygen reduction reaction.

ABSTRACT: The oxygen reduction reaction limits the energy efficiency of H₂ fuel cells and Li-air batteries, yet, it remains poorly understood within popular kinetic frameworks. Here, we study the oxygen reduction reaction on Pt/C, Ir/C, Ru/C and Rh/C nanoparticles as a function of electrochemical bias, temperature and O₂ pressure at industrially-relevant conditions in membrane electrode assemblies. Bias-, and pressure-dependent Arrhenius analysis reveals distinct changes in the (apparent) activation energy and pre-exponential factor that we relate to kinetics that cascade through a series of rate-limiting steps and transition states. Further, while the kinetics are accelerated by the pressure and bias, they remain pinned to pseudo-capacitive reduction processes and structural c

SUBMITTER: Silva Olaya AR 

PROVIDER: S-EPMC12708627 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature