Abstract:The intermetallic compound Zr_1−xHf_xCo and Zr_1−xSc_xCo (x=0, 0.1, 0.2, 0.3) were prepared and their suitability for hydrogen storage was investigated. The alloys show single cubic phase identical with ZrCo by X-ray diffraction. Pressure- composition-temperature(PCT) measurement results show that the equilibrium dehydrogenation pressure of Zr_1−xHf_xCo alloy increases obviously with increasing Hf content while it, changes little with increasing Sc content for Zr_1−xSc_xCo alloy. The dehydrogenation temperatures for supplying 100 kPa hydrogen are about 673, 627, and 650 K for ZrCo, Zr_0.7Hf_0.3Co and Zr_0.7Sc_0.3Co alloy, respectively. Thermodynamics calculation results indicate that dehydrogenation ΔH for Zr_1−xHf_xCo alloy decreases with increasing Hf content but increases with increasing Sc content for Zr_1−xSc_xCo alloy, which are coincident with their dehydrogenation property. The maximal hydrogen storage capacity of both Zr_1−xHf_xCo and Zr_1−xSc_xCo alloy at room temperature are high enough.

Key words: hydrogen storage alloy; ZrCo; Zr_1−xHf_xCo; Zr_1−xSc_xCo; intermetallic compound