Investigation of the Hydrogen Storage and Oxygen Poisoning Resistance Properties of Zr 1– x Y x Co ( x = 0–0.15) Alloys

ZrCo alloys are widely recognized as ideal hydrogen isotope storage candidates for the International Thermonuclear Experimental Reactor (ITER). However, their practical application is severely hindered by hydrogen desorption effects and surface poisoning caused by impurity gases. This study developed Zr1–xYxCo (x = 0–0.15) alloys through rare earth element Y microalloying and systematically investigated the relationship between structure and properties. Results demonstrated that the optimal Y substitution (x = 0.05) significantly enhanced initial hydrogen absorption kinetics, reducing the saturation time from 50,189 s to 2,445 s─a reduction of approximately 95%. Additionally, the Zr0.95Y0.05Co alloy exhibited excellent antidesorption performance, maintaining its hydrogen storage capacity after 13 h at 500 °C. In terms of impurity resistance, the optimized alloy achieved an 85.3% capacity retention rate after 50 cycles in H2 + 1000 ppm of O2 atmosphere, significantly outperforming the original ZrCo alloy (23.4%). XPS analysis revealed a “self-sacrifice” mechanism, where Y preferentially forms a dense Y2O3 protective layer. This layer effectively inhibits oxygen diffusion while preserving the metallic state of the active Zr and Co sites. These findings suggest that Zr0.95Y0.05Co is a potential material for robust hydrogen isotope storage and transport systems.