Defects mediated enhanced catalytic and humidity sensing performance in ceria nanorods

The content of defects and manipulation of oxygen vacancies in ceria (CeO₂) nanomaterials through doping have been widely used as effective strategies to rationally control its reactivity for diverse applications. In this work, a facile and simple fabrication method of CeO₂ nanorod crystals is demonstrated where; defects content and oxygen vacancies were tailored by doping with transition metal (Iron, Fe) ions. The effect of Fe-doping level (Ce_0.95Fe_0.05O₂ and %, Ce_0.9Fe_0.1O₂) on the structural, morphological, and optical properties of ceria nanorods was explored in detail. Undoped and Fe-doped CeO₂ nanorods were further explored for their use in photocatalytic activity and humidity sensing applications. The results revealed superior photocatalytic activity of Ce_0.9Fe_0.1O₂ by showing about 90% degradation of organic dye within 80 min of reaction time. Further, the same sample demonstrated excellent humidity sensing capabilities with faster response (~19 s) and recovery rate (~ 49 s) at 100% humidity conditions than other investigated samples. This work presents a systematic study on the fluencies of Fe doping in CeO₂ nanorod crystals to better understand the role of oxygen vacancies for tailoring their structural and optical properties for proficient environmental and sensing applications.