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Is it possible to attract oxygen molecules or to displace them effectively?
Question Date: 2020-01-06
Answer 1:

The process of a molecule contacting a surface and sticking to it is called adsorption. Whether a molecule will adsorb to a surface depends on many factors, including the atomic composition and charge of both the molecule and the surface. For example, a positively charged protein is likely to adsorb onto a negatively charged glass surface. In the case of oxygen molecules (O2), the molecules are not charged, but they still adsorb onto some surfaces, such as platinum.

To displace an adsorbed molecule, including oxygen, a good method is to introduce another molecule that adsorbs even more strongly to the surface. That molecule would then replace the oxygen, leaving the oxygen free to leave the surface. Another method is to heat the surface. When a surface becomes hot enough, molecules that are adsorbed tend to leave.

Whether or not you want oxygen to adsorb onto a surface depends on what you are using that surface for. In some cases, oxygen adsorption can be a good thing. Some chemical reactions involving oxygen depend on the presence of a catalyst—a material that enables or speeds up a reaction. For reactions involving oxygen that occur on the surface of the catalyst, oxygen must first adsorb onto the catalyst surface before the reaction can take place. For example, one of the first reactions involving a catalyst that was discovered was the combination of hydrogen gas and oxygen gas in the presence of a platinum surface. On the surface, the hydrogen and oxygen combine to form water, a reaction that depends on both the hydrogen and oxygen gases adsorbing onto the platinum surface.

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