Modulating Built‐In Electronic Configuration via Variable Al Doping for Robust Oxygen Evolution Reaction

Abstract Transition metal‐based electrocatalysts play a crucial role in the oxygen evolution reaction (OER). However, their heavy reliance on free electrons at the d ‐band significantly limits the screening of potentially efficient, earth‐abundant alternatives. Despite extensive exploration of catalyst engineering through multi‐metal cooperation to modulate electron configuration by introducing additional transition metals, practical success remains elusive. Here, we present a straightforward electrodeposition method for preparing amorphous FeCoAl hydroxide catalysts. The introduction of Al contributes external free electrons, enabling a well‐defined electron configuration for intermediate adsorption. Al doping also adjusts the d ‐band position of adjacent Co atoms, bringing them closer to the Fermi level and significantly enhancing intrinsic activity at the active sites. Furthermore, Al dopants facilitate rapid mass and charge transfer near the catalyst layer, promoting faster reaction kinetics. Leveraging these properties, the FeCoAl hydroxide catalyst achieves a large current density of 100 mA cm −2 at an overpotential of 340 mV, with a small Tafel slope of 29.1 mV dec −1 . Our work provides valuable insights for designing efficient electrocatalysts by leveraging free electron‐rich metal doping and expanding the parameter space for catalyst engineering.