Interfacial Built‐In Electric Field and Interatomic Charge Transfer Synergistically Boosting Oxygen Evolution on CeO ₂ /Ce‐Co ₃ O ₄ Electrocatalyst

Abstract Boosting oxygen evolution reaction (OER) performances of transition metal‐based electrocatalysts via charge localization regulation is an effective strategy to reduce the cost of hydrogen production through water electrolysis, but still remains great challenging. Herein, a CeO 2 /Ce‐Co 3 O 4 OER electrocatalyst decorated with CeO 2 nanoparticles and Ce single atoms has been fabricated using one deposition and calcination method. The as‐obtained heterojunction structure of CeO 2 /Ce‐Co 3 O 4 triggers interfacial built‐in electric field and as‐introduced Ce single atoms induce the charge transfer in Co‐O‐Ce configurations, thus tremendously tuning the electron localization of the Co sites. As expected, the CeO 2 /Ce‐Co 3 O 4 catalyst exhibits superior performances toward OER in alkaline condition, achieving a current density of 10 mA cm −2 at an overpotential of only 216 mV, and demonstrating outstanding long‐term stability for 100 h. Density functional theory and in‐situ spectroscopic results confirm that the co‐existence of heterojunction structure and single atom doping can contribute to electron localization and d band centers upshift of Co sites, thereby leading to the increased adsorption energy, lowered reaction barrier, and more proportion of lattice oxygen mechanism pathway. This work reveals the application and perspective of regulating spinel electronic structures via interfacial built‐in electric field and interatomic charge transfer for large‐scale OER applications.