Synergistically manipulating the d-p orbitals via interface and defect engineered CeO2 NPs@Nickel hydroxide for enhanced ampere-level oxygen evolution

Elevating the lattice oxygen p -band center (ε p ) is critical to trigger the lattice oxygen mechanism (LOM) for boosting oxygen evolution reaction (OER) activity in advanced electrocatalysts, but it also causes a reduced d -band center (ε d ) due to the coupled metal-oxygen d - p orbital, resulting in a sluggish regeneration of lattice oxygen. Herein, we surmount this challenge by heterojunction and defect-engineering to raise both ε d and ε p of CeO 2 NPs/D-Ni(OH) 2 . The formative built-in electric field and defect reduce the electronic density of Ni(OH) 2 , effectually decreasing the deprotonation energy and promoting its surface reconstruction into γ-NiOOH, the formative high valence Ni δ+ raises ε p to trigger LOM. Meanwhile, the ε d is upshifted by the high f -band of CeO 2 , accelerating the adsorption of oxygenous species to replenish the lattice oxygen vacancies. Consequently, the CeO 2 NPs/D-Ni(OH) 2 demonstrates exceptional OER activity, requiring only 169 mV to reach 10 mA cm −2 , and maintains impressive stability over 300 h at 1000 mA cm −2 in 1 M KOH. This work presents a novel strategy to balance lattice oxygen participation and regeneration by rising d - p orbital for inducing and maintaining LOM activity.