Catalytic reduction of NO over Mn-V-Ce/TiO₂ catalysts at low reaction temperature

A novel Mn-V-Ce/TiO₂ catalyst for selective catalytic reduction (SCR) of nitric oxide was prepared by impregnation method. The effects of reaction temperature, NO and O2 concentrations, NH₃/NO ratio and space velocity on Mn-V-Ce/TiO₂ catalytic activity were studied. The SCR reaction mechanism on this catalyst was explored with transient response reaction of NO, O₂, and NH₃. The effect of H₂O and SO₂ on the catalyst activity was investigated using FT-IR and TG techniques. Experimental results showed that Mn-V-Ce/TiO₂ catalyst has good SCR activity at low temperature. High NO conversion of over 99.2% were observed at 150℃ and space velocity 5000h^－1. When both SO₂ and H₂O were added in feed gas, the NO conversion could be kept over 98% at 170℃ for 350min. However, it was observed that the loss of catalytic activity was quick when SO₂ was added in feed gas alone; while 8% H₂O alone in feed gas had little negative effect on the catalytic activity, which was always over 98% at this situation.The catalyst is expected to be applied in the removal of NOx from exhaust gas without SO2 at low temperature, such as exhaust gas from nitric acid production process or boilers of natural gas.