Boosting Hydrogen Oxidation Activity of Ni in Alkaline Media through Oxygen‐Vacancy‐Rich CeO₂/Ni Heterostructures

The search for highly efficient platinum group metal (PGM)‐free electrocatalysts for the hydrogen oxidation reaction (HOR) in alkaline electrolytes remains a great challenge in the development of alkaline exchange membrane fuel cells (AEMFCs). Here we report the synthesis of an oxygen‐vacancy‐rich CeO 2 /Ni heterostructure and its remarkable HOR performance in alkaline media. Experimental results and density functional theory (DFT) calculations indicate the electron transfer between CeO 2 and Ni could lead to thermoneutral adsorption free energies of H* (Δ G H* ). This, together with the promoted OH* adsorption strength derived from the abundance of oxygen vacancies in the CeO 2 species, contributes to the excellent HOR performance with the exchange current density and mass activity of 0.038 mA cm Ni −2 and 12.28 mA mg Ni −1 , respectively. This presents a new benchmark for PGM‐free alkaline HOR and opens a new avenue toward the rational design of high‐performance PGM‐free electrocatalysts for alkaline HOR.