Simultaneous removal of NO and Hg0 over Nb-Modified MnTiOx catalyst

Abstract

Removal of NO and Hg0 simultaneously was achieved on Nb-modified MnTiOx catalyst. Experimental results revealed that high NO conversion (>95%) and Hg0 oxidation (>95%) in 200–300 °C were available on Mn0.15Nb0.02TiOx catalyst with a GHSV of 108,000 h−1. The excellent catalytic performance of Mn0.15Nb0.02TiOx catalyst should be originated from its high reducibility and massive surface chemisorbed oxygen species. Moreover, the introduction of Nb into MnTiOx catalyst greatly enhanced its resistance to SO2 and H2O. Neither gaseous Hg0 nor HgO formed on catalyst surface could affect the NH3-SCR reaction. NO had a promotion effect on Hg0 oxidation, while NH3 was detrimental to Hg0 oxidation owing to the inhibited adsorption of Hg0 by NH3. Under SCR reaction conditions, an inhibition impact on Hg0 oxidation could be detected, but this negative effect could be avoided by using more catalyst sample.