In a hydrogen alkaline fuel cell, the components are typically arranged in the following order:
Anode: The anode is the negative electrode in the fuel cell where the oxidation reaction takes place. In a hydrogen alkaline fuel cell, the anode is usually made of a porous carbon material, such as graphite, coated with a catalyst, commonly platinum (Pt). The anode facilitates the splitting of hydrogen molecules (H2) into protons (H+) and electrons (e-).
Electrolyte: The electrolyte in a hydrogen alkaline fuel cell is an alkaline solution, typically potassium hydroxide (KOH) or sodium hydroxide (NaOH). It allows the flow of hydroxide ions (OH-) between the anode and the cathode. The electrolyte must be conductive to facilitate the movement of ions.
Membrane: The membrane in a hydrogen alkaline fuel cell is a critical component that separates the anode and the cathode while allowing the passage of ions. It needs to be ionically conductive and impermeable to gas. The most common membrane used in alkaline fuel cells is a polymer membrane, such as Nafion, which is made of a perfluorosulfonic acid polymer.
Cathode: The cathode is the positive electrode in the fuel cell where the reduction reaction occurs. In a hydrogen alkaline fuel cell, the cathode is typically made of porous carbon material, similar to the anode, and coated with a catalyst, often platinum (Pt). The cathode facilitates the reaction between oxygen from the air and the protons and electrons from the anode, producing water (H2O).
To summarize, the correct order of the components in a hydrogen alkaline fuel cell is:
Anode → Electrolyte → Membrane → Cathode
It's important to note that fuel cell designs may vary, and there are different types of alkaline fuel cells with variations in the materials and construction of the components. The above description provides a general overview of a hydrogen alkaline fuel cell.