Is the ∗O vs. ∗OH scaling relation intercept more relevant than the ∗OOH vs. ∗OH intercept to capture trends in the oxygen evolution reaction?

The transition from fossil fuels to renewable energy sources is inevitable, and electrocatalytic water splitting to produce hydrogen is one of the core processes that must be further optimized. Regrettably, the anodic oxygen evolution reaction (OER) severely limits its efficiency. Theory explains the humble intrinsic activity of OER catalysts by scaling relations between reaction intermediates. While the scaling relation between the ∗OOH and ∗OH intermediates is well established, only the slope of the ∗O vs.∗OH relation has an estimated numerical value, whereas the intercept of this scaling relation is frequently assumed to be zero. Herein, we demonstrate how deviations from this assumption cause changes in the shape of the volcano plot and the prevalent mechanisms at the apex of the volcano plot. Our derived volcano plots may enable further progress in the design of OER catalysts by shifting focus on the intercept of the ∗O vs. ∗OH scaling relation.