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Abstract: In order to modified the acid–base properties of pure cerium dioxide, a series of ceria-based oxides doped with gallium(III) cations (from 5 to 50% mol/mol of Ga) was prepared by co-precipitation in basic aqueous solution followed by calcination at 773K. N2 physisorption at 77K showed that mesoporous materials with surface areas between 75 and 104m2/g were obtained. Ga(III) cations were incorporated into the ceria crystal structure up to a concentration close to 20–25% mol/mol of Ga, as revealed by powder X-ray diffraction analysis. Surface basicity was investigated using CO2 chemisorption by mass spectrometry and in situ infrared spectroscopy. A progressive decrease in the surface basicity in the series of ceria–gallia materials was observed as the Ga content increases. Different carbonate and bicarbonate surface species were identified through their vibrational infrared modes. A remarkable decrease in the surface stability of carbonate species, particularly of the polydentate carbonate groups, was detected, which is correlated to the incorporation of gallium(III) into the ceria lattice. [Copyright &y& Elsevier]

Abstract: This work presents the synthesis and characterization of cerium oxide doped with gallium, which were prepared by co-precipitation in basic aqueous solution followed by calcination at 773K. XRD and Raman spectroscopy suggested that Ga(III) cations were incorporated into the ceria crystal structure. Moreover, surface Ga-H species were detected by FTIR with a 100cm−1 downshift of the ν(Ga-H) peak, which indicated that Ga(III) were incorporated onto the surface lattice of the ceria. Results of CO2 and CO chemisoption, as well as, TPR-H2 and TPR-CO, showed that the acid–base (decreased basicity) and redox (enhanced reducibility) properties of the gallium-doped ceria materials were modified as compared with the pure cerium dioxide. The catalytic oxidation of CO was investigated over the oxides. [ABSTRACT FROM AUTHOR]