Coordination Engineering of Ru-N-C Based OER Catalysts Guided by the ∆G*OH Descriptor: A Theoretical Study

Abstract

Ru-N-C single-atom catalyst is intrinsically limited in the oxygen evolution reaction (OER) by excessively strong oxygen adsorption, which renders the *O → *OOH step rate-determining. Here, we systematically modulate the Ru center through five distinct coordination strategies: axial non‑metal, axial metal, axial N‑bridged metal, in‑plane dual‑metal, and in‑plane N‑bridged dual-metal motifs. Guided by the ΔG*OH descriptor (1.23-1.53 eV) (Journal of Colloid and Interface Science, 2023, 640, 170-178 ), we screen over 100 structures and evaluate full OER pathways and stability. Specifically, (i) Axial CH3 and NH groups lower overpotential (η) to 0.58 V and 0.59 V, with binding energies ΔEb = -6.42 eV and -6.08 eV; (ii) Axial Mn, Fe, Co, Ni, Cu give η = 0.38-0.48 V, among which Ru‑N4Mn‑C achieves η = 0.38 V and ΔEb = -5.59 eV; (iii) Axial N‑bridged Ni and Cu produce η ≈ 0.50 V and exceptionally high ΔEb ≈ -9.20 eV; (iv) In‑plane N‑bridged oxidized structures, especially RuIr‑O3, exhibit an ultra‑low o η of 0.18 V (ΔEb = -4.24 eV), while RuRh‑O3R(Rh) and RuIr‑O3R(Ir) balance η = 0.55 V/0.37 V with ΔEb = -6.42 eV/-5.92 eV. Cross‑system comparison identifies Ru‑NiN4 and RuIr‑O3R as top integrated performers. Operando simulations reveal that *O specific adsorption, especially when coupled with an electric field (0.3 V/Å), weakens metal‑support binding by up to 2.2 eV, while ab initio molecular dynamics confirms the dynamic stability of RuIr‑O3R (±0.03 eV over 5000 fs). This work provides a quantitative library of Ru‑based OER catalysts and establishes *O‑induced destabilization as the primary degradation mechanism.