Influence of calcination and pretreatment conditions on the activity of Co3O4 for CO oxidation

• Published in: Chinese journal of catalysis 2013-02, Vol.34 (2), p.283-293
• Main Authors: YU, Yunbo, ZHAO, Jiaojiao, HAN, Xue, ZHANG, Yan, QIN, Xiubo, WANG, Baoyi
• Format: Article
• Language: English
• Subjects: Calcination; Carbon monoxide oxidation; Oxygen vacancy; Pretreatment; Tricobalt tetraoxide
• ISSN: 1872-2067; 1872-2067
• DOI: 10.1016/S1872-2067(11)60484-1

The influence of calcination and pretreatment conditions on the structure of Co3O4 and its activity for CO oxidation were studied. TG analysis indicated that the precursor of Co3O4 prepared by a precipitation method was present in the form of cobalt hydroxide carbonate, calcination of which within the temperature range of 150–400 °C in air resulted in the formation of cubic phase Co3O4. N2 adsorption-desorption, powder X-ray diffraction, transmission electron microscopy, and activity test results showed that the prepared Co3O4 samples were comprised of nanoparticles, with the specific surface area and size distribution closely related to the calcination temperature. Over these samples, a size dependence of the catalytic activity for CO oxidation was clearly observed. As identified by positron annihilation lifetime spectrum, low temperature oxygen temperature-programmed desorption, and durability testing for CO oxidation, pretreatment of Co3O4 in N2 within the temperature range 150–250 °C favors the formation of surface oxygen vacancy clusters, the occurrence of which would be beneficial for the adsorption and activation of O2, and also for the catalytic oxidation of CO. Meanwhile, the reconstruction of oxygen vacancies on the surface of Co3O4, induced by the pretreatment process, was also discussed.