Generation of ternary Pr-Mo-O oxides by solid state reactions between oxide powders under ultrasonic stirring

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and scanning electron microscopy are used to prove that the ultrasound used for the preparation of molybdenum- and praseodymium-based heterogeneous multiphase catalysts can induce solid-state reactions at room. temperature between the binary oxides Pr6O11 and MoO3. Turbulent flows and shock waves produced by the ultrasonic cavitation are thought to cause particles to collide into one another and to generate local temperatures which are sufficiently high far inducing interparticle melting. Unequivocal evidence is provided by ToF-SIMS that the ultrasonic dispersion leads to the surface formation of the praseodymium molybdate phase Pr2Mo3O12.