Structure and surface chemistry in crystalline mesoporous (CeO2−δ)–YSZ

Mesoporous metal oxides (CeO2−δ)–YSZ have been synthesized by a versatile direct synthesis method using ionic cetyltrimethylammonium bromide (CTAB) and different nonionic (block copolymers) as surfactants and urea as hydrolyzing agent. The synthesis was realized at pH = 9 using tetraethylammonium hydroxide (TEAOH) as pH mediator. Calcination at 550 °C led to the formation of crystalline metal oxides with uniform mesoporosity. The obtained materials have been characterized by thermogravimetric analysis (TG-DTG), wide and small-angle X-ray diffraction (XRD), Raman spectroscopy, Brunauer, Emmett and Teller (BET) surface area analysis, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). All the obtained materials exhibits mesoporous structure, crystalline structure indexed in a cubic symmetry, showing a high surface area, a uniform and narrow pore size distribution, spherical morphology typical for the mesoporous materials. The crystalline and mesoporous structures, surface chemistry and stoichiometry for the samples synthesized using ionic and nonionic surfactants have been discussed.

Mesoporous metal oxides (CeO2−δ)–YSZ have been synthesized by a versatile direct synthesis method using ionic and nonionic surfactants and urea as hydrolyzing agent. All the samples highlighted a crystalline structure, indexed in a cubic symmetry in which Zr4+ is replaced by Ce4+ and Y3+ is replaced by Ce3+, respectively.Figure optionsDownload high-quality image (107 K)Download as PowerPoint slideHighlights
► Mesoporous (CeO2−δ)–YSZ obtained by direct synthesis surfactants assisted.
► After calcinations at 550 °C crystalline metal oxides with uniform mesoporosity.
► Average pore size diameter around 6 nm.
► A strong interaction between elements indexed in a cubic symmetry, fluorite type.
► A good incorporation of ceria in YSZ lattice, with a Ce3+ amount around 30%.