Simultaneous removal of elemental mercury and NO in simulated flue gas over V2O5/ZrO2-CeO2 catalyst

A series of V/ZrCex catalyst synthesized by a co-precipitation method was employed to investigate the simultaneous removal of NO and elemental mercury (Hg-0) in simulated flue gas. The catalysts were characterized using BET, SEM, XRD, H-2-TPR, XPS, and FT-IR. V/ZrCe0.6 with CeO2/ZrO2 molar ratio of 0.6 showed excellent SCR activity (87.3%) and high Hg oxidation efficiency (77.6%) in SCR atmosphere (NH3/NO = 1). The results indicated that the Hg had little impact on NO conversion, while the coexistence of NO and O-2 would be beneficial for the Hg oxidation. Hg oxidation was inhibited in SCR atmosphere owing to the presence of NH3. The characterization results demonstrated that the superior performance of V/ZrCe0.6 catalyst might be attributed to lower crystallinity, better texture properties, strong redox ability and high reactive nitrate together with NH3 species. The redox equilibrium (Ce3+ + V5+ <-> Ce4+ + V4+) contributed to the NO conversion and Hg oxidation. The bidentate sulfates formed by adsorbed SO2 could provide new acid sites for NH3 adsorption and increase the amount of NH4+, which reduced the poisoning effect of SO2 and H2O. Based on the experimental results, a mechanism for the simultaneous removal of NO and Hg was proposed for the V/ZrCe0.6 catalysts: 2NH(3)/NH4+(ad) + NO2(ad) + NO(g) -> 2N(2) + 3H(2)O+/2H(+), Hg(ad)+O beta -> HgO(ad). (C) 2016 Elsevier B.V. All rights reserved.