First-principles calculations and experiments for Ce4+ effects on structure and chemical stabilities of Zr1-xCexSiO4

Using Ce atom as the surrogate for tetravalence actinides, the structure stability, chemical bonding and solubility of Zr 1- x Ce x SiO 4 have been investigated by combing first principles calculations and static leach test (MCC-1) experimentally to understand the effect of actinides on stability of ZrSiO 4 . The structural analysis indicates that the high symmetry of [CeO 8 ] polyhedron could well maintain the structural stability of Zr 1- x Ce x SiO 4 . However, due to the longer and weaker Ce O bond than Zr O bond, LR Ce is slightly higher than LR Zr . Besides, the LR Zr and LR Ce are highest in acid leaching solution , followed in alkaline leaching solution and deionized water system. Worth noted, the negative solution energy of −22.254 eV indicates the pre-existing Zr vacancy is energetically favorite to accommodate actinides surrogate Ce impurities or quadrivalent actinides with slight structural deformation, showing the strong structural and chemical stabilities of ZrSiO 4 .