Room-temperature dilute magnetic semiconductor behavior in nonmagnetic Ti4+-doped CeO2 nanoflowers for efficient spintronics and photocatalytic applications

Abstract

This study investigates the synthesis and characterization of Ti-doped CeO₂ nanoflowers (Ce_1-xTi_xO₂, x = 0, 0.01, 0.03, and 0.05) prepared via a hydrothermal method. Characterization techniques, including XRD, TEM, XPS, and Raman spectroscopy, confirmed the successful incorporation of Ti into the CeO₂ lattice, leading to the formation of pure CeO₂ nanoflowers with cubic structure and an increase in oxygen vacancies. The optical band gap of the doped nanoflowers decreased from 3.27 to 3.07 eV. Room temperature ferromagnetism was observed in Ce_1-xTi_xO₂ nanoflowers (x = 0.01, 0.03, and 0.05). Notably, the x = 0.05 composition exhibited a remarkable 376% increase in ferromagnetism, reaching 55 × 10⁻³ emug⁻¹ at 15 kOe. This ferromagnetism is likely attributed to the oxygen vacancies created by doping, which trap charges and lead to the formation of F-centers. These F-centers then interact with impurity atoms, enhancing the magnetic properties. Increased Ti-doping resulted in a noticeable quenching of photoluminescence intensity, indicating improved charge carrier separation. This enhanced separation contributed to the photocatalytic activity of the synthesized samples, which was assessed by methylene blue degradation under UV light. The sample with x = 0.05 exhibited the highest photocatalytic activity. These findings suggest that Ti-doped CeO₂ based diluted magnetic semiconductors hold promise for applications in spin-based electronics, optoelectronics and photocatalysis.

Graphical Abstract

Substitution driven enhanced magnetic and photocatalytic properties in Ti⁴⁺-doped CeO₂ nanoflowers.