Experimentally and Theoretically Revealing the Co-Doping Effects of Ce–Sr in Gd₂Zr₂O₇

Abstract

To safely dispose radioactive waste (including, e.g., thorium and radiostrontium), Ce4+ and Sr2+ were chosen as simulated surrogates of α and β waste and were introduced into the Gd3+ site in Gd2Zr2O7 to maintain the average cationic radius and to compensate for charge. A series of Gd2–x Sr x/2Ce x/2Zr2O7 (0.00 ≤ x ≤ 0.25) compounds were examined by experimental and theoretical calculations to investigate the co-doping effects of α and β waste in a Gd2Zr2O7-based matrix. The effects of Ce4+ and Sr2+ content on the phase, unit cell parameters, active modes, mechanical property, and microstructure were studied systematically. Moreover, the limit of incorporation of Ce4+ and Sr2+ in Gd2Zr2O7 pyrochlore and the lattice parameters were also calculated through virtual crystal approximation theory, and the results were found to well agree with experimental results.

Abnormal thermal expansion coefficients in (Nd1−xDyx)2Zr2O7pyrochlore: The effect of low-lying optical phonons

“…The real space force constants were calculated by the finite displacement method using a 2×2×2 supercell (176 atoms). The real space force constants for (Nd0.5Dy0.5)2Zr2O7 were estimated from the results obtained for Nd2Zr2O7 and Dy2Zr2O7 via a virtual crystal approximation (VCA) method, which has been proved to be applicable in the doped pyrochlore system [28]. The phonon properties were obtained from the calculated real space force constants by using the software PHONOPY [29].…”

Influence of Nano-CeO2 and Graphene Nanoplatelets on the Conductivity and Dielectric Properties of Poly(vinylidene fluoride) Nanocomposite Films

“…Among various rare earth elements, cerium (Ce) is one of the most important compounds that has found great potential for numerous applications . Nanosized cerium oxide (CeO 2 ) is regarded as the most exuberant rare earth metal oxide which has attracted tremendous attention owing to its nontoxicity, reliability, high surface area, and low cost in addition to excellent thermal and electrical properties compared to the bulk Ce. − CeO 2 has a cubic structure similar to fluorite, where O 2– ions are present on the surface of Ce 4+ in FCC arrangements. , On account of its incredible properties such as excellent thermal stability, good electrical conductivity, ion diffusion, and optical characteristics, nano-CeO 2 has been frequently used in extensive applications such as energy storage, fuel cells, semiconductor devices, and gas sensors. , Moreover, nanosized CeO 2 holds great promise in the fabrication of polymer nanocomposites (PNCs), where it has been used as an active nanofiller to improve the properties of various polymer matrices for biomedical, gas sensing dielectric, and electrochemical applications. , …”

“…5−7 CeO 2 has a cubic structure similar to fluorite, where O 2− ions are present on the surface of Ce 4+ in FCC arrangements. 8,9 On account of its incredible properties such as excellent thermal stability, good electrical conductivity, ion diffusion, and optical characteristics, nano-CeO 2 has been frequently used in extensive applications such as energy storage, fuel cells, 10 semiconductor devices, 11 and gas sensors. 12,13 Moreover, nanosized CeO 2 holds great promise in the fabrication of polymer nanocomposites (PNCs), where it has been used as an active nanofiller to improve the properties of various polymer matrices for biomedical, 14 gas sensing 15 dielectric, 16 and electrochemical applications.…”