Anisotropic growth of gas-liquid precipitated ceria mesocrystals to wires several micrometers in length

Abstract

Ceria (CeO2) wires with lengths of 6 μm and diameters of tens of nanometers are fabricated through the anisotropic growth of mesocrystals. In the gas-liquid precipitation process, an aqueous Ce(NO3)3 solution is used as a starting material and NH3 gas is used to induce CeO2 precipitation at the gas-liquid interface. CeO2 mesocrystals, formed by this process at 60 °C, grow in the direction of 〈011〉 into micrometer length wires exposing {001} and {011} on their side walls. It is shown that the initial pH of the starting material solution is a key parameter to attain anisotropic growth of the CeO2 mesocrystals. We thus propose the formation mechanism of micrometer length-CeO2 wires from mesocrystals.