Πολλαπλές εισόδους και εξόδους. Το υδρογόνο εισέρχεται μέσω της εισόδου H και. Cutaway diagram of a hydrogen (H? ) fuel cell. The structure features a cylindrical metal body with multiple inlets and outlets. Hydrogen enters through the H? Inlet and passes over a ceramic substrate coated with precious group metals (PGM). A catalyst bed facilitates the reaction, producing water (H? O) that exits through two outlets. The design efficiently manages the flow of gases, highlighting key components such as the catalyst and PGM coating, crucial for hydrogen-oxygen reactions in fuel cells.