Synthesis of Ca-doped spinel by Ultrasonic Spray Pyrolysis

Author(s)

Camargo, M. T. T. ^[1] ; Jacques, Q. ^[1] ; Caliman, L. B. ^[1] ; Miagava, J. ^[1] ; Hotza, D. ^[2] ; Castro, R. H. R. ^[3] ; Gouvea, D. ^[1]

Affiliation

^[1] Univ Sao Paulo, Polytech Sch, Dept Met & Mat Engn, Av Prof Mello Moraes 2463, BR-05508030 Sao Paulo, SP - Brazil

^[2] Fed Univ Santa Catarina UFSC, Dept Chem Engn EQA, BR-88040900 Florianopolis, SC - Brazil

^[3] Univ Calif Davis, Dept Chem Engn & Mat Sci, Davis, CA 95616 - USA

• Document type: Journal article
• Source: Materials Letters; v. 171, p. 232-235, MAY 15 2016.
• Web of Science Citations: 6

Abstract

MgAl2O4 is a stable catalyst support with potential for replacing gamma-alumina in several applications. However, synthesis of magnesium spinel requires elevated temperatures to avoid phase separation (in MgO and Al2O3) at low temperatures, leading to coarsening and reduction of active surface area. In this work, nano CaO-doped and undoped magnesium aluminate were successfully prepared by Ultrasonic Spray Pyrolysis (USP), using a simple adapted experimental set-up operating at 1100 degrees C. During the process, the particles stay at high temperatures for a short period of time, allowing phase stability and limited coarsening. The influence of calcium oxide on the particles morphology and structure was investigated via X-ray diffraction, N-2 adsorption, X-ray fluorescence, scanning electron microscopy and transmission electron microscopy. The spinel nanopowders were obtained as spherical porous agglomerates of similar to 1 mu m. The resulting powder showed low crystallite sizes in the 5-10 nm range and high specific surface area from 110.0 to 76.6 m(2) g(-1). (C) 2016 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 13/23209-2 - Ions segregation onto oxide nanopowders surfaces and the influence on the colloidal processing
• Grantee: Douglas Gouvêa
• Support Opportunities: Regular Research Grants