Ce-Co interaction effects on the catalytic performance of uniform mesoporous Cex-Coy catalysts in Hg0 oxidation process

Abstract Ce 1 -Co 3 catalyst prepared by template method has been proved to have a good Hg 0 removal efficiency due to its large surface area and plenty of surface active sites. However, the strong interaction between Ce and Co has a significant influence on physicochemical property and Hg 0 removal efficiency, and the interaction mechanism has not been thoroughly explained to date. To understand the interaction mechanism of Ce and Co, Ce-Co catalysts with different Ce/Co molar ratios were prepared by the template method. N 2 adsorption, XRD, TEM, HRTEM, XPS and H 2 -TPR were used to investigate physicochemical properties of the catalysts. Catalysts with very different molar amounts of Ce and Co (like Ce 1 -Co 6 and Ce 6 -Co 1 ) had more lattice defects resulting in more surface active sites. But they had non-uniform mesoporous channels and a low BET surface area leading to a large mass transfer resistance. In contrast, similar molar amount of Ce and Co leaded to uniform mesoporous channels and a much larger BET surface area, but less surface active sites (like Ce 1 -Co 1 ). Furthermore, high Ce concentration leaded to a high crystallinity of CeO 2 , a low specific surface area and a non-uniform pore structure due to the sintering of CeO 2 . And more Co introduction enhanced the redox properties at low temperature. For these reasons, Ce 1 -Co 3 had the best Hg 0 oxidation efficiency and the widest temperature window, which was more than 90% in the temperature range of 150–400 °C.