Evidence of novel crystal structure in cesium-doped sodium zirconate perovskite and its impact in optical and CO₂ sorption properties

The synthesis and crystallographic stability of Cs⁺-doped Na₂ZrO₃ perovskite were explored to enhance optical properties and CO₂ sorption at low temperatures (500 °C). Perovskite nanoparticles ( \(\sim\) $\sim$ 20 nm) crystallize in monoclinic C 2/c symmetry and undergo a partial transformation to a new rhombohedral (Hex) \(R\overline{3 }m\) $R\overline{3}m$ symmetry during synthesis. The newly obtained atomic coordinates are discussed with respect to their Wyckoff site multiplicity. The incorporation of Cs⁺ significantly improves perovskite stability (from t = 0.807 to t = 0.916). Optical band gap analysis reveals a reduction in photon energy from 3.91 to 3.54 eV, making it a promising photonic material due to its low phonon energy ( \(\ge 430 {{\text{cm}}}^{-1}\) $\ge 430{\text{cm}}^{-1}$ ). Additionally, Cs concentration induces a porous structure that enhances CO₂ capture capacity, as observed in CO₂ sorption analysis.