Research on the catalytic oxidation of Hg⁰ by modified SCR catalysts

A series of metal oxides were employed to modify the commercial SCR catalyst, and the Ce modified SCR catalyst was selected and then subjected to detailed catalytic oxidation of Hg⁰ by using the simulated flue gas. The results indicated that the catalytic activity of the catalyst was increased remarkably after the Ce modification, and the highest catalytic oxidation of Hg⁰ was obtained from the modified SCR catalyst with 9% Ce loading, being 40% higher than that of the non-modified SCR catalyst. The BET and XRD analysis indicated that the surface area of the 1%~9% Ce modified SCR catalyst was no significant change compared with the non-modified SCR catalyst, and the CeO₂ was well dispersed on the catalyst surface, without any aggregation. The flue gas condition had great effects on the Hg⁰ conversion. The catalytic oxidation of Hg⁰ would be significantly increased by HCl, and also increased as the increasing of the temperature in a certain range. The highest catalytic oxidation efficiency reached 95.11% at the optimal space velocity, temperature and flue gas components. In addition, the CeO₂ doping did not affect the denitration efficiency of the SCR catalyst.