Effects and mechanism of Ti, Cu, Y, La, Ce, Pr, Nd and Sm substitutions on the anti-disproportionation performance of ZrCo alloy

The intermetallic compound ZrCo is widely considered a good choice to substitute uranium in storing gaseous tritium. Whereas the storage capacity fading induced by the disproportionation reaction which happens during the hydriding and dehydriding processes becomes the main obstacle to overcome at the present stage. In this work, the effects and mechanism of Ti, Cu, Y, La, Ce, Pr, Nd and Sm substitutions on the anti-disproportionation performance of ZrCo alloy were carefully investigated by combining experiments and first-principles calcula-tions. By the investigation of Zr1-xTixCo (x = 0, 0.05, 0.10, 0.15 and 0.20), it is confirmed that the increase of Zr-H (8e) bond length and decrease of 8e site size are beneficial to prevent the access of H into the 8e site of ZrCoH3, which helps the improvement of anti-disproportionation performance. It has shown that rare-earth elements are preferred to substitute Zr than Co atom in ZrCo and ZrCoH3 compounds. While alloying rare-earth elements may not contribute significantly to the enhancement of the anti-disproportionation property of ZrCo alloy. Additionally, the charge density distribution and polarized density of states of undoped and doped ZrCoH3 crystals were clarified.