Additive-Free Synthesis of Cerium Oxide Nanorods with Reaction Temperature-Tunable Aspect Ratios

The ability to control the morphology of fluorite-structured cerium oxide nanomaterials is an important step in the design of cerium oxide-based catalysts. Herein, we report an additive-free synthesis of cerium oxide nanorods with highly tunable aspect ratios from ~6:1 to 40:1. The use of a microwave hydrothermal method allows for both rapid synthesis and temperature control. The ability to control the length of the nanorods from 1.7 μm by varying only the reaction temperature was demonstrated over a temperature range of 80°C to 200°C. The formation of the resulting nanorods was investigated using selected-area electron-diffraction and high-resolution transmission electron microscopy. The surface area of nanorod products was found to decrease from 117 to 22 m2/g as the reaction temperature increased from 80°C to 200°C, complementing the general trend of the increasing aspect ratios of these products.