The microscopic electrode process of oxygen evolution reaction
(OER) is crucial for the rational design of efficient multiscale systems
in modern electrocatalysis, which needs to be elaborately clarified,
especially for catalysts with various components. In this work, beginning
with electrochemical redox behavior analysis of nickel species, the
active function of multicomponent catalysts (here carbon-contained
FeNi-based metals/hydroxides) for OER was elucidated. The component
FeNi layered double hydroxides experienced in situ electrochemical
transformation, which were further verified as actual species for
dominating OER. By kinetic modeling, the surface reactive intermediate
*OH featured a volcano plot with an increase in potential, while *O
emerged to a saturated coverage to ensure unhindered progress of the
rate-determining step (*O → *OOH), thus endowing the overall
OER with a fast rate. This case study facilitates understanding of
the fundamental activities of a multicomponent electrode on the electrocatalytic
reaction, which contributes to developing novel materials for future
application in electrochemical energy conversion and storage.