Iron can rust even without the presence of a catalyst. Rusting is a specific form of oxidation that occurs when iron reacts with oxygen in the presence of water or moisture. However, the rate of rusting is generally accelerated by the presence of certain catalysts, such as electrolytes (e.g., salts) or acids, which increase the conductivity of the solution and facilitate the electron transfer process.
In a container filled with 100% oxygen, there would still be some oxidation occurring on the surface of the iron. Oxygen is a key component required for the rusting process to take place. However, the absence of water or moisture would significantly slow down the rate of rusting. Moisture is essential because it allows the formation of an electrolytic medium that facilitates the electron transfer reactions involved in rusting.
Without moisture, the process of rusting would be greatly inhibited or even prevented. However, it's important to note that even in a dry environment, certain forms of oxidation can still occur on the surface of iron, although at a much slower rate compared to when moisture is present. These reactions typically form thin layers of iron oxide, such as FeO (iron(II) oxide) or Fe3O4 (iron(II,III) oxide), which are generally less extensive than the typical rust formation.
So, in summary, while the absence of moisture would slow down the rusting process, some oxidation reactions can still occur on the surface of iron in the presence of oxygen, forming thin oxide layers.