V‐Integration Modulates t2g‐Electrons of a Single Crystal Ir1‐x(Ir0.8V0.2O2)x‐BHC for Boosted and Durable OER in Acidic Electrolyte

Abstract Realizing efficacious π ‐donation from the O 2 p orbital to electron‐deficient metal (t 2g ) d ‐orbitals along with separately tuned adsorption of *O and *OOH, is an imperious pre‐requisite for an electrocatalyst design to demonstrate boosted oxygen evolution reaction (OER) performance. To regulate the π ‐donation and the adsorption ability for *O and *OOH, herein, a facile strategy to modulate the electron transfer from electron‐rich t 2g ‐orbitals to electron‐deficient t 2g ‐orbitals, via strong π ‐donation from the π ‐symmetry lone pairs of the bridging O 2− , and the d ‐band center of a biomimetic honeycomb (BHC)‐like nanoarchitecture (Ir 1‐ x (Ir 0.8 V 0.2 O 2 ) x ‐BHC) is introduced. The suitable integration of V heteroatoms in the single crystal system of IrO 2 decreases the electron density on the neighboring Ir sites, and causes an upshift in the d ‐band center of Ir 1‐ x (Ir 0.8 V 0.2 O 2 ) x ‐BHC, weakening the adsorption of *O while strengthening that of *OOH, lowers the energy barrier for OER. Therefore, BHC design demonstrates excellent OER performance (shows a small overpotential of 238 mV at 10 mA cm −2 and a Tafel slope of 39.87 mV dec −1 ) with remarkable stability (130 h) in corrosive acidic electrolyte. This work opens a new corridor to design robust biomimetic nanoarchitectures of modulated π ‐symmetry (t 2g ) d ‐orbitals and the band structure, to achieve excellent activity and durability in acidic environment.