A comparative study of Fm-3m TiO2, ZrO2, HfO2, and CeO2 via atomistic modeling

Abstract

Metal oxides (XO2) have been extensively studied experimentally and theoretically. However, atomistic insights into systems like ZrO2 and CeO2, critical in nanocatalysis, remain incomplete. Using ab initio density functional theory (DFT) with the FP-LAPW method in the Wien2k framework and the PBE exchange-correlation functional, we examined the physical and chemical properties of cubic Fm-3m oxides (XO2, X = Ti, Zr, Hf, Ce). Lattice parameters increase with atomic mass except for HfO2, which deviates due to stronger ionic bonding. ZrO2 is the stiffest, followed by HfO2, TiO2, and CeO2. Electronic analysis shows TiO2’s narrow band gap (1.15 eV), ZrO2 and HfO2’s wide gaps (3.16 and 3.77 eV), and CeO2’s moderate gap (2.17 eV) with redox activity. PDOS analysis highlights O 2p and metal d-/f-orbital interactions. These results emphasize distinct properties influencing their applications in photocatalysis, dielectrics, and catalysis, warranting further exploration