Thorough
analyses of structural factors in catalysis are interesting
because they allow the massive prescreening of potential optimum compositions.
Overall, this article shows how the orbital physics of magnetic compositions
relates with spin–lattice interactions and then band gaps and
bond lengths together become relevant descriptors in catalytic oxygen
technologies. Active electrocatalysts for the oxygen evolution reaction
(OER) include magnetic oxides with metals at relatively high oxidation
states, so chemisorbed molecular O2 is not very stable.
On the other hand, ideal compositions for the oxygen reduction reaction
(ORR) have metals in a comparatively lower oxidation state, which
can supply electrons to activate O2 molecules toward electron-richer
oxygen atoms. Spin–lattice interactions in these strongly correlated
oxides relate the orbital configurations and oxidation state with
distinctive metal–oxygen bond distances, indicating localized
or itinerant electronic behavior and selectivity in oxygen electrochemistry.
OER at low overpotentials coincides with anti-Jahn–Teller contractions
in ferromagnetic (FM) metal–oxygen (M–O) bonds; however,
active oxides for ORR have longer FM M–O bonds, electron-richer.
In both cases of OER and ORR, dominant FM couplings moderate the binding
energies of the reactants because of the stabilizing quantum spin-exchange
interactions associated with the open-shell orbital configurations,
and correspondingly, their catalytic efficiencies improve in accordance
with Sabatier’s principle. The presence of FM holes in the
M–O bonds also enhances spin-selective charge transport, the
other crucial enthalpic contribution in electrocatalysis. These specific
effects of spin-dependent potentials in heterogeneous catalysis define
the explicit field of spintro-catalysis, needed to allow the inclusion
of strongly correlated electrons in theoretical models, and as we
show here also with the advantage of the recognizing structural descriptors
ligated to spin–lattice interactions.