Surface tuning of LaCoO 3 perovskite by acid etching to enhance its catalytic performance

Abstract 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 CoO x /LaCoO 3 catalyst.