The stoichiometric LaCoO_(3) and nonstoichiometric LaCo_(1.2)O_(3) perovskite catalysts were prepared by citric acid sol-gel method,and then,LaCoO_(3) perovskite was etched with nitric acid.The structure,surface compo...The stoichiometric LaCoO_(3) and nonstoichiometric LaCo_(1.2)O_(3) perovskite catalysts were prepared by citric acid sol-gel method,and then,LaCoO_(3) perovskite was etched with nitric acid.The structure,surface composition and reducibility of the catalyst were studied by X-ray diffraction(XRD),nitrogen desorption,transmission electron microscope(TEM),temperature program reduction of H_(2)(H_(2)-TPR) and X-ray photoelectron spectroscopy(XPS).It was found that nitric acid etching did not change the crystal structure and the overall morphology of the LaCoO_(3) catalyst,but it can cause the exposure of B-site Co metal to the surface of the catalyst.As a result,after acid etching,the reducibility of the LaCoO_(3) catalyst was improved,leading to the improvement in the catalytic activity of the LaCoO_(3) catalyst for CO oxidation and C_(3)H_(8) combustion.Moreover,the catalytic activity of the LaCoO_(3) catalyst after acid etching was higher than that of LaCo_(1.2)O_(3) and CoOx/LaCoO_(3) catalyst.展开更多
基金financially supported by the National Key Research and Development Program of China(No.2016YFC0204300)China National Tobacco Corporation Major Projects(No.110201501001)。
文摘The stoichiometric LaCoO_(3) and nonstoichiometric LaCo_(1.2)O_(3) perovskite catalysts were prepared by citric acid sol-gel method,and then,LaCoO_(3) perovskite was etched with nitric acid.The structure,surface composition and reducibility of the catalyst were studied by X-ray diffraction(XRD),nitrogen desorption,transmission electron microscope(TEM),temperature program reduction of H_(2)(H_(2)-TPR) and X-ray photoelectron spectroscopy(XPS).It was found that nitric acid etching did not change the crystal structure and the overall morphology of the LaCoO_(3) catalyst,but it can cause the exposure of B-site Co metal to the surface of the catalyst.As a result,after acid etching,the reducibility of the LaCoO_(3) catalyst was improved,leading to the improvement in the catalytic activity of the LaCoO_(3) catalyst for CO oxidation and C_(3)H_(8) combustion.Moreover,the catalytic activity of the LaCoO_(3) catalyst after acid etching was higher than that of LaCo_(1.2)O_(3) and CoOx/LaCoO_(3) catalyst.
