Oxide surface modification: Synthesis and characterization of zirconia-coated alumina

• Published in: Journal of colloid and interface science Vol. 343; no. 1; pp. 256 - 262
• Main Authors: Dalmaschio, Cleocir José, Mastelaro, Valmor R., Nascente, Pedro, Bettini, Jefferson, Zotin, José Luiz, Longo, Elson, Leite, Edson Roberto
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.03.2010; Elsevier
• Subjects: Aluminum oxide; Catalysis; Ceramics; Chemistry; Coating; Colloidal state and disperse state; Crystal structure; Dispersion; Exact sciences and technology; General and physical chemistry; Impregnation; Oxides; Surface; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; X-ray photoelectron spectroscopy; Zirconium dioxide; Zirconium oxides; Coating; Catalysis; Ceramics; Dispersion; Surface; Modification; Binary compound; Support; Oxides; X ray; Precursor; Characterization; Zirconium oxide; Synthesis; Photoelectron spectrometry; Resins; Ceramic materials; Catalytic reaction; Transition element compounds; Transition metal; X ray diffraction; Zirconia; Impregnation; Zirconium; Transmission electron microscopy; Phase separation; Models; Alumina
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2009.11.027

Diagrams built from the proposed model for surface modification of oxide for a coating composed of ZrO 2 and experimental results obtained by XRD for the coating of aluminas. Four aluminas were used as supports for impregnation with a zirconium oxide with the aim to achieve a coating, without phase separation, between support and modifier. The supports were impregnated with different concentrations of zirconium aqueous resin, obtained through the polymeric precursor method. After impregnation the samples were calcined and then characterized by XRD, which led to identification of crystalline zirconia in different concentrations from each support used. Using a simple geometric model the maximum amount of surface modifier oxide required for the complete coating of a support with a layer of unit cells was estimated. According to this estimate, only the support should be identified below the limit proposed and crystalline zirconium oxide should be identified above this limit when a complete coating is reached. The results obtained from XRD agree with the estimated values and to confirm the coating, the samples were also characterized by EDS/STEM, HRTEM, XPS, and XAS. The results showed that the zirconium oxide on the surface of alumina support reached the coating in the limit of 15 Zr nm −2, without the formation of the ZrO 2 phase.