F127 assisted synthesis of Bi promoted Co3O4 catalyst for catalyzing N2O decomposition in presence of impurity gases

Abstract

In this paper, Bi promoted Co₃O₄ catalysts used for catalyzing N₂O decomposition were successfully prepared by improved sol-gel method with the assistance of F127. It was found that the doping of additive Bi not only did not change the unique “Yardang Landform” microstructure of the 3.0F-Co₃O₄, but also prompted Co₃O₄ to expose more active crystal planes, such as (422), (533) and (620). Moreover, the doping of the additive Bi also enhanced the catalyst's specific surface area, and further weakened the surface Co-O bond. The optimum 3.0F-Bi_0.015Co catalyst achieved >88 % N₂O conversion (2000 ppmv N₂O/Ar, GHSV=20,000 h⁻¹) at 300 °C, and its corresponding TOF value increased from 1.50 × 10⁻³ s⁻¹ for 3.0F-Co₃O₄ to 3.63 × 10⁻³ s⁻¹. Meanwhile, the E_a of 3.0F-Bi_0.015Co was as low as 47.0 kJ mol⁻¹. Most importantly, the catalyst has good resistance to O₂ and H₂O. Under the harsh condition (both 5 vol.% O₂, 100 ppmv NO and 2 vol.% H₂O were coexisted in the reaction system), the N₂O conversion over the 3.0F-Bi_0.015Co catalyst can be stable above 90 % at 400 °C.