Dispersion of ceria nanoparticles on gamma-alumina surface functionalized using long chain carboxylic acids

摘要

Dispersion and stability of nanoparticles on a support is determined by the interaction between these phases. In case of hydrophobic nanoparticles (e.g. synthesized by reverse microemulsion method) the interaction with hydrophilic support (e.g. gamma-Al2O3) is weak and agglomeration as well as poor resistance to sintering may cause problems. The bonding of the particles to the support may be effectively strengthened by proper modification of the support, e.g. by adsorption of hydrophobic compounds on its surface. In this work decanoic, myristic, stearic and oleic acid were used for the first time to cover gamma-Al2O3 surface in order to enhance the dispersion of ceria nanoparticles deposited afterward by impregnation on such support. TGA and FTIR methods revealed that at monolayer coverage (1.1-2.5 molecules per nm(2)) the acid molecules are firmly bounded to the alumina surface. Morphology, textural properties, phase composition and reducibility of the CeO2/gamma-Al2O3 samples were investigated using TEM, SEM, BET, XRD and H-2-TPR methods. It has been shown that deposition of CeO2 nanoparticles on gamma-Al2O3 surface covered with all studied acids enhances its dispersion, stability and reducibility. The most effective modification of the gamma-Al2O3 surface was obtained at loading of 2.3 molecules of decanoic acid per nm(2) of the support. (C) 2016 Elsevier B.V. All rights reserved.