Single-atom catalysts dispersed on an oxide support are essential for overcoming the sluggishness of the oxygen evolution reaction (OER). However, the durability of most metal single-atoms is compromised under harsh OER conditions due to their low coordination (weak metal-support interactions) and excessive disruption of metal-O_lattice bonds to enable lattice oxygen participation, leading to metal dissolution and hindering their practical applicability. Herein, we systematically regulate the local coordination of Ir_single-atoms at the atomic level to enhance the performance of the OER by precisely modulating their steric localization on the NiO surface. Compared to conventional Ir_single-atoms adsorbed on NiO surface, the atomic Ir atoms partially embedded within the NiO surface (Ir_emb-NiO) exhibit a 2-fold increase in Ir-Ni second-shell interaction revealed by X-ray absorption spectroscopy (XAS), suggesting stronger metal-support interactions. Remarkably, Ir_emb-NiO with tailored coordination sphere exhibits excellent alkaline OER mass activity and long-term durability (degradation rate: ∼1 mV/h), outperforming commercial IrO₂ (∼26 mV/h) and conventional Ir_single-atoms on NiO (∼7 mV/h). Comprehensive operando X-ray absorption and Raman spectroscopies, along with pH-dependence activity tests, identified high-valence atomic Ir sites embedded on the NiOOH surface during the OER followed the lattice oxygen mechanism, thereby circumventing the traditional linear scaling relationships. Moreover, the enhanced Ir-Ni second-shell interaction in Ir_emb-NiO plays a crucial role in imparting structural rigidity to Ir single-atoms, thereby mitigating Ir-dissolution and ensuring superior OER kinetics alongside sustained durability.

A new Ru oligomer of formula {[Ru^II(bda-κ-N²O²)(4,4′-bpy)]₁₀(4,4′-bpy)}, 10 (bda is [2,2′-bipyridine]-6,6′-dicarboxylate and 4,4′-bpy is 4,4′-bipyridine), was synthesized and thoroughly characterized with spectroscopic, X-ray, and electrochemical techniques. This oligomer exhibits strong affinity for graphitic materials through CH−π interactions and thus easily anchors on multiwalled carbon nanotubes (CNT), generating the molecular hybrid material [email protected] . The latter acts as a water oxidation catalyst and converts to a new species, 10′(H₂O)₂@CNT, during the electrochemical oxygen evolution process involving solvation and ligand reorganization facilitated by the interactions of molecular Ru catalyst and the surface. This heterogeneous system has been shown to be a powerful and robust molecular hybrid anode for electrocatalytic water oxidation into molecular oxygen, achieving current densities in the range of 200 mA/cm² at pH 7 under an applied potential of 1.45 V vs NHE. The remarkable long-term stability of this hybrid material during turnover is rationalized based on the supramolecular interaction of the catalyst with the graphitic surface.