Insight on the growth mechanism of TiO2 nanoparticles via gaseous detonation intercepting collection

In a closed tube, TiO2 nanoparticles can be prepared by hydrolyzing TiCl4 under extreme conditions of hydrogen -oxygen explosion. In this process, the chemical reaction is complex and violent, and TiO2 nanoparticles can achieve particle growth and phase transition in a very short time. The photocatalytic activity of TiO2 is closely related to its particle size and phase composition, however, it is difficult to observe the growth process of TiO2 in the explosion process. An intercepting collection scheme was proposed to explore the growth mechanism of TiO2 nanoparticles during gaseous detonation. The characterization results illustrated that the TiO2 nanoparticles were successfully collected by the intercepting device. The particle size of intercepted powders is smaller than that of the powders precipitated on the tube wall, and as the distance between the intercept position and the initiation point increases, the particle size decreases. The growth of TiO2 nanoparticles closely depends on the propagation and attenuation of detonation wave. After detonation nucleation and combustion sintering, TiO2 nanoparticles with anatase phase and rutile phase are fabricated. The proposed intercepting collection method is helpful to reveal the dynamic growth mechanism of nanomaterials under the extreme conditions of gaseous detonation.