What fuel and oxidant does a hydrogen-oxygen fuel cell use?

A hydrogen-oxygen fuel cell utilizes hydrogen as the fuel and oxygen as the oxidant in its electrochemical reaction. In this type of fuel cell, hydrogen molecules are fed into one side of the cell, where they undergo oxidation, releasing electrons and forming protons. The electrons travel through an external circuit, generating electricity, while the protons move through an electrolyte to the other side of the cell. At the cathode (the other side), oxygen molecules combine with the protons and the electrons to form water as a byproduct.

This process illustrates why hydrogen and oxygen are specifically suited for use in fuel cells: they create a clean energy source that produces water as the only emission, making it environmentally friendly. In contrast, the other combinations suggested do not facilitate this clean energy conversion as effectively.