CePO4 Catalyst for Elemental Mercury Removal in Simulated Coal-Fired Flue Gas

Abstract

CePO4 catalyst (termed Ce–P–O) was for the first time employed to capture elemental mercury (Hg0) under simulated coal-fired flue gas conditions. As compared with commercial SCR catalyst (i.e., V–W–Ti), the Ce–P–O catalyst showed a much better performance in Hg0 removal. The high Hg0 adsorption capacity, abundant active oxygen species, and excellent SO2 poisoning resistance account for the performance of the Ce–P–O catalyst. When the catalyst was subjected to individual flue gas component conditions, it was found that the presence of NO can significantly improve the Hg0 removal efficiency over the Ce–P–O catalyst; however, HCl did not show promotion effect. It is proposed that the former occurs because the generated NO2 (originated from NO oxidation) could react with Hg0 ad-species (e.g., Hg2O), regenerating the HgO and hence enhancing the Hg0 chemisorption. The latter was found to be due to the absence of the Deacon reaction over the catalyst.