Continuous-Flow Synthesis of Thermochromic M-Phase VO2 Particles via Rapid One-Step Hydrothermal Reaction: Effect of Mixers

Abstract EN

VO2 particles are promising materials for thermochromic smart windows that reduce building energy loss.

Continuous-flow hydrothermal processes showcase advantages for synthesizing VO2 particles compared with traditional batch reaction systems.

Mixers play a crucial role in particle fabrication in continuous-flow systems.

In this study, a Center T-Mixer and a Collision Cross-Mixer are developed and implemented in a hot water fluidized suspension reaction (HWFSR) system.

The influence of the resident time on the particle phase and size was evaluated, and properties of particles derived from systems equipped with differing mixers were compared.

The resulting particles were characterized using techniques of X-ray powder diffraction (XRD) analysis, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC).

When compared with the Center T-Mixer, results indicate that the Collision Cross-Mixer has better control regarding the morphology and size distribution of resulting particles while improving the transition temperatures of the as-synthesized materials.

HWFSR systems containing novel mixer designs are capable of producing pure M-phase VO2 particles in a single step contrary to the current reactor design that use a second postheat treatment step, and they are capable of synthesizing many other nanoparticle species, especially those requiring high temperature and pressure reaction conditions.