Silica-supported ceria–zirconia and titania–zirconia nanocomposites: Structural characteristics and electrosurface properties

A series of CeO2–ZrO2/SiO2 and TiO2–ZrO2/SiO2 nanocomposites was synthesized using a liquid-phase method and characterized using nitrogen adsorption–desorption, X-ray diffraction, thermogravimetry, XRF spectrometry, FTIR spectroscopy, SEM, particle size (D) distribution measured with QELS, zeta (ζ) potential and surface charge density (σ) methods. Structural characteristics (phase composition, average size of crystallites) of the materials affected by pre-heating were determined from the XRD data. Samples TiZrSi1 (TiO2:ZrO2:SiO2 = 3:10:87) and TiZrSi2 (10:10:80) calcined at 550 °С are amorphous. Samples CeZrSi1 (CeO2:ZrO2:SiO2 = 3:10:87) and CeZrSi2 (10:10:80) include a crystalline (Zr0.4Ce0.6)O2 phase. This finding is in a good agreement with SEM analysis. The crystallite size depends slightly on treatment temperature. The influence of changes in the phase composition, sizes and surface structure of particles, surface charge density and zeta potential in aqueous suspensions of nanocomposites is observed as a shift of the isoelectric point (pHIEP) and changes in the shape of σ and ζ curves vs. pH.