Comparative computational and experimental insights into the structural, electrical, and biological properties of CeO2 fluorite ceramics
Raj Kumar, V. K. Gupta, Mohit Khosya, Sangeeta Singh, Upendra Kumar
Abstract
A comprehensive comparative study was conducted on synthesized (CS) and commercially procured (CP) cerium oxide (CeO₂) samples, and evaluating their computational, structural, microstructural, biocompatibility, and electrical properties. First-principles computational studies revealed that CS exhibited greater volume optimization than CP, although both samples demonstrated a band gap of 2.4–2.5 eV, consistent with the semiconducting nature of CeO₂. The density of states analysis indicated a strong hybridization between Ce-4f and O-2p orbitals, with CS, displaying enhanced electronic density near the Fermi level. X-ray diffraction studies followed by Rietveld refinement confirmed the fluorite structure. Microstructural analysis showed dense, agglomerated morphologies in both samples. However, CS exhibited a higher oxygen content than CP, implying variation in defect concentrations. FTIR confirmed phase purity with characteristic Ce–O vibrations at 435 and 1631 cm¹, while Raman spectroscopy supported this by revealing the F₂g mode (~ 465 cm¹) typical of fluorite-structured CeO₂. Electrical impedance spectroscopy revealed higher ionic conductivity in CS, with a lower grain boundary blocking factor (αgb = 0.42) compared to CP (αgb = 0.62), likely due to differences in defect density and microstructure. Biocompatibility tests showed that CeO₂-300 (CS) had the highest inhibitory efficacy (IC₅₀ ≈ 65.94 µg/ml), followed by CeO₂-800 (≈ 74.1 µg/ml) and CeO₂-Pure (CP) (≈ 86.88 µg/ml), indicating the influence of synthesis on biological response. These results highlight the critical impact of synthesis methods on the biocompatibility and electrical performance of CeO₂ materials useful as solid electrolyte in IT-SOFCs application.