Controlled One-Step Synthesis of Monodisperse CeO₂ Octahedra in a Binary Solvent System with Waste Liquid Recycling

Area of Science:

• Materials Science
• Nanotechnology
• Inorganic Chemistry

Background:

• Template-dependent and anion-assisted methods for cerium dioxide (CeO2) synthesis have limitations.
• Developing efficient and environmentally friendly synthesis routes for morphology-controlled nanomaterials is crucial.

Purpose of the Study:

• To present a novel solvent-controlled strategy for the one-step solvothermal synthesis of octahedral CeO2.
• To achieve morphology control without using auxiliary templates or surfactants.
• To establish a green and practical method for oxide synthesis.

Main Methods:

• Solvothermal synthesis using cerium(III) nitrate hexahydrate (Ce(NO3)3·6H2O) in methanol/water (MeOH/H2O) mixtures.
• Optimization of solvent composition, temperature (180 °C), and reaction time (3-24 h).
• Characterization using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM).

Main Results:

• Phase-pure cubic CeO2 with well-defined octahedral morphology was exclusively obtained in a 15 mL MeOH/5 mL H2O system.
• Other alcohols (ethanol, n-propanol, isopropanol) resulted in irregular aggregates.
• Crystallinity improved between 3 and 24 h, with subsequent surface dissolution.
• The solvothermal mother liquor was recycled four times without loss of product quality.

Conclusions:

• A green and practical solvent-controlled solvothermal strategy enables the one-step synthesis of octahedral CeO2.
• This method offers precise morphology control and reduces solvent consumption.
• The findings contribute to sustainable synthesis of advanced oxide nanomaterials.