Abstract:
Titanate nanotubes were synthesized hydrothermally with commercial TiO
2 nanoparticles in NaOH; after calcination at 400℃, TiO
2 nanotubes were obtained and used as the support to prepare manganese catalyst (MnO
x/TiNT) by wet-impregnation for low temperature selective catalytic reduction of NO (SCR). The results of BET, TEM, XRD and TG measurements showed that TiO
2 nanotubes exhibit well-defined TiO
2 anatase phase after calcination at 400℃ and manganese particles are highly dispersed on the wall of TiO
2 nanotubes. The effects of active component loading, space velocity, oxygen content, \NH
3\/\NO\ ratio and NO concentration on the SCR performance of MnO
x/TiNT were investigated in a simulated flue gas. Under the reaction conditions of 150℃, \NH
3\/\NO\ of 1.2, \O
2\ of 3%, \NO\ of 0.06%, GHSV of 23613.8h
-1 and Mn loading of 5%~15%(mass ratio), NO conversion exceeds 95%. The catalyst is deactivated in the presence of H
2O at 180℃, but its activity can be recovered almost completely when cutting off H
2O; higher resistance to H
2O is observed at higher temperature. The presence of SO
2 can also deactivate the catalyst gradually; however, the catalyst exhibits better resistance toward SO
2 in the presence of H
2O than that without H
2O. The SCR activity of MnO
x/TiNT catalyst deactivated by SO
2 rises gradually after cutting off H
2O + SO
2, but cannot be recovered to its initial level.