The stoichiometric LaCoO3 and nonstoichiometric LaCo1.2O3 perovskite catalysts were prepared by citric acid sol–gel method, and then, LaCoO3 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 H2 (H2-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 LaCoO3 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 LaCoO3 catalyst was improved, leading to the improvement in the catalytic activity of the LaCoO3 catalyst for CO oxidation and C3H8 combustion. Moreover, the catalytic activity of the LaCoO3 catalyst after acid etching was higher than that of LaCo1.2O3 and CoOx/LaCoO3 catalyst.

中文翻译：

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通过酸蚀刻对 LaCoO3 钙钛矿进行表面调整以提高其催化性能

通过柠檬酸溶胶-凝胶法制备化学计量的 LaCoO3 和非化学计量的 LaCo1.2O3 钙钛矿催化剂，然后用硝酸蚀刻 LaCoO3 钙钛矿。通过X射线衍射（XRD）、氮气脱附、透射电子显微镜（TEM）、H2程序升温还原（H2-TPR）和X射线光电子能谱（XPS）等手段研究了催化剂的结构、表面组成和还原性. 发现硝酸蚀刻不会改变LaCoO3催化剂的晶体结构和整体形貌，但会导致B位Co金属暴露在催化剂表面。结果，酸蚀后，LaCoO3催化剂的还原性得到提高，从而提高了LaCoO3催化剂对CO氧化和C3H8燃烧的催化活性。而且，