Hindered sintering behaviors of titania nanoparticle-based materials

AbsatractPorous material sintering is gaining more attraction because of the need for catalyst supports, sensors, solar cells, or other desired interactions with the enviroment. In this study, anatase TiO2 nanoparticle suspensions are cast and sintered into porous materials. Surprisingly, suspension preparation condition has a drastic effect on sintered grain size, relative density, and shrinkage. When the suspension is prepared at basic condition with polyacrylic acid (PAA) as the dispersant, the sample shows faster shrinkage with much larger grain sizes. When the suspension is prepared at acidic condition with polyethylene glycol (PEG) as the dispersant, the sample has much slower shrinkage with minimal grain growth. The fundamental cause is the special organic residuals adsorbed on particle surfaces. This provides a simple yet extremely effective approach to produce nano grain-sized and highly porous materials.

► TiO2 nanoparticle suspension drastically affects sintered grain size and density.
► Basic condition with polyacrylic acid has faster shrinkage and larger grain size.
► Acidic condition with polyethylene glycol has slower shrinkage and grain growth.
► Organic residuals on particles are the cause for the sintering differrence.
► The work offers an approach to produce nanograin and highly porous materials.