Hydrogen Storage and Release Properties of a Cu-Added Fe/YSZ Redox System

Figure 5

XRD patterns of the samples (a) before the reaction with Cu/Fe/12YSZ, (b) after the first reduction of (a), and (c) after the first oxidation of (b) (●: Fe₂O₃, ○: YSZ, ▼: Fe, □: Fe₃O₄, ◆: Cu).