Confinement–Induced N₂–Phobicity Enables O₂ Extraction from Air for Catalysis

However, only 20.9% of air is oxygen and approximately 78% is nitrogen gas, which is inert and is often used to isolate oxygen. We report that N₂–phobicity together with confinement–catalysis exponentially increases the power density of H₂–air fuel cells by selectively transporting oxygen from the air into a confined space.

N₂–phobicity originates from a combination of low nitrogen diffusion within ordered 1D pores and the unusual confined nanospace with electron–rich Pt–N states that enhance the electrostatic repulsion force to nitrogen. The resulting fuel cell exhibited the highest mass activity, the lowest durability decline, and a record high current density of 707 mA cm^–2 at 0.8 V.