Fig. 5.

Mechanism of O₂ reduction to water by the MCOs. Broad arrows indicate the steps that take place in the catalytic cycle of the MCOs; thin arrows indicate steps that can be experimentally observed but are not part of the catalytic cycle. The peroxy intermediate is a 2e⁻-reduced species, and the native intermediate is a 4e⁻-reduced species. Adapted from [34] with the author’s permission