Ageing-assisted room temperature synthesis of La₂Mo₂O₉ powders

Without any templates, hollow structured La₂Mo₂O₉ particles are successfully prepared at room temperature by an ageing-assisted salt solvent process. Powder X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy are used to investigate structure and morphologies of the obtained products. It is found that the ageing process has a significant influence on the particle morphology evolution when the mixed precursors are disposed at room temperature. With the ageing time changed from one week to 12 weeks, the particles morphologies evolve gradually from ellipsoid to sphere. The as-prepared hollow structured La₂Mo₂O₉ spheres have an average diameter of about 800 nm and shell thickness of about 100 nm. For elucidating the possible formation mechanism, the influences of the single salt on the particles morphologies evolution are also investigated. The final results indicate KCl is a key factor for formation of La₂Mo₂O₉ spheres and the formation of the hollow structure should have close relations with the surface tension in the ageing assisted process. - Highlights: • Ageing-assisted salt solvent process was designed to prepare La₂Mo₂O₉. • Hollow structured La₂Mo₂O₉ micro-spheres are synthesized at room temperature for the first time. • The possible formation mechanism was discussed.