<p><a></a><a>The oxygen evolution reaction (OER) is the bottleneck
that limits the energy efficiency of water-splitting. The process involves four
electrons’ transfer and the generation of triplet state O<sub>2</sub> from
singlet state species (OH<sup>- </sup>or H<sub>2</sub>O). Recently, explicit
spin selection was described as a possible way to promote OER in alkaline
conditions, but the specific spin-polarized kinetics remains unclear. </a><a></a><a>Here, we report that </a><a>by
using ferromagnetic ordered catalysts as the spin polarizer for spin selection
under </a><a></a><a>a
constant magnetic field</a>, <a>the OER can be enhanced.</a> However, it does not applicable to non-ferromagnetic
catalysts. We found that the spin <a>polarization occurs at
the first electron transfer step in OER</a>, where <a></a><a>coherent spin exchange
happens </a>between the <a></a><a>ferromagnetic</a> catalyst and the
adsorbed oxygen species <a>with fast kinetics</a>, under the principle of spin angular momentum
conservation. In the next three electron transfer steps, as the adsorbed O
species adopt fixed spin direction, the OER electrons need to follow the Hund
rule and Pauling exclusion principle, thus to carry out spin polarization
spontaneously and finally lead to the generation of triplet state O<sub>2</sub>.
Here, we showcase spin-polarized kinetics of oxygen evolution reaction, which gives
references in the understanding and design of spin-dependent catalysts.</p>