Enhancing Transparency and Reversible Valence Control of Uranium in Bulk Ceramics via Cerium‐Induced Lattice Expansion

Abstract The control of uranium's valence state is critical for applications requiring tunable optical or catalytic behaviors, which is hindered by the lattice distortion and opacity introduced by uranium ions, limiting the development of heavy particle detectors. In this work, these challenges are addressed by employing cerium as a lattice expansion ion, which not only enhances the transparency of the uranium‐doped ceramics but also enables reversible control over uranium's valence state under high uranium doping concentration. This approach mimics catalytic reactions, allowing for precise tuning of the ceramic's optical properties. It is demonstrated that the introduction of cerium successfully expands the crystal lattice to incorporate mismatched uranium, enhancing the integral ceramic transparency and catalyzing the reversible uranium valence.