Surface characterization of LaCoO3 synthesized using citric acid

In preparation for synthesizing LaCoO3, gel was prepared by adding citric acid to the aqueous solution of La(NO3)3·6H2O and Co(NO3)2·6H2O. The infrared spectrum indicates that the gel prepared with 0.007 mol of citric acid is the mixture of LaCo(C6H5O7)(NO3)3, lanthanum nitrate, and cobalt nitrate, while the gel prepared with 0.011 mol of citric acid is LaCo(C6H5O7)2. Perovskite-type LaCoO3 was obtained by firing the gel above 600°C. The LaCoO3 surface was characterized by X-ray photoelectron spectroscopy and with respect to the catalytic activity of CO oxidation.