Characterization of CeO2 doped MgAl2O4 prepared by the chelating agents-assisted impregnation method

ALEJANDRA VILLAGRAN OLIVARES; BARROSO M. NOELIA; ABELLO M. CRISTINA

QUíMICA NOVA

SOC BRASILEIRA QUIMICA

Lugar: San Pablo; Año: 2018 vol. 41 p. 899 - 904

0100-4042

MgAl2O4 spinel employed as support of reforming catalysts was modified by CeO2. Thesamples were prepared by wet impregnation from aqueous solutions of cerium nitrate,with and without chelating agents. The chelating agents used were ethylenediaminetetraaceticacid (EDTA), nitrilotriacetic acid (NTA) and citric acid (CA) at different pHof impregnation. The solids were characterized by TG, XRD, SBET, TPR, SEM-EDXand CO2−TPD. Nanoparticles of CeO2 between 5 and 6.8 nm were obtained by thethermal decomposition in air at 600°C. The surface cerium reduction occurred in a widetemperature range of 450° to 670°C. The use of citric acid at pH= 8 led to the lowestparticle size of CeO2 and the lowest interaction with the spinel. The H2 consumptionand extent of Ce-support interaction did not show a clear dependence with the CeO2particle sizes. The use of chelating agents in the impregnation step did not modify thetotal basicity. Slight changes in the strength of weak basic sites were observed.