[CO-SCR Performance and Mechanism over Co3O4 Catalysts].

Nitrogen oxide (NOx) is an important precursor for many air pollution problems such as fine particulate matter and ground-level ozone. Because air pollution levels increase daily, it is important to control NOx emissions from industrial boiler flue gas. A series of different Co3O4 catalysts was prepared in this study by different methods. The effects of the preparation methods on selective catalytic reduction of NO by CO (CO-SCR) were investigated. The catalysts were characterized by BET, XRD, HR-TEM, and Raman. The results show that the Co3O4-S catalyst, prepared by solid grinding with cobalt sulfate as the precursor, had better CO-SCR activity and H2O resistance and that Co3O4-C, prepared by solid grinding with cobalt acetate as the precursor, showed excellent H2O resistance. The NO oxidation results showed that better NO oxidation activity over the catalysts is an important reason for the improved CO-SCR activity. The Raman results indicate that more Co2+ ions appeared on the surface of Co3O4-S, which benefited the formation of oxygen vacancies. The H2-TPR results showed better redox property of the Co3O4-S catalyst. The HR-TEM results shoes that the (111) and (220) crystal planes were exposed mainly on Co3O4-S and Co3O4-O and that more (220) crystal planes are conducive to improved reaction.