Transition Metal Doped MnO_x-CeO₂ Catalysts by Ultrasonic Immersing for Selective Catalytic Reduction of NO with NH₃ at Low Temperature

Transition metals doped Mn-based catalysts were prepared via ultrasonic immersing method for the selective catalytic reduction (SCR) of NO_x from fuel gas. The Catalysts’ DeNO_x efficiency and tolerance to sulfur were investigated in the paper. XRD results demonstrate high dispersion of Mn, Ce and M (Pr, Y, Zr, W) elements on TiO₂ carrier, which is favor for reduction of active materials content. Mn-Ce-W catalyst presents uniform particle size about 500 nm to 800 nm from SEM pictures and shows the best NO_x conversion of 93.2% at 200°;C and 98.4% at 250°;C, respectively. Sulfur tolerance analysis indicated that transition metals M can improve the catalysts’ performance when 0.01% SO₂ exists in the fuel gas, because metal doping into the Mn-Ce catalyst can inhibit the sulfate deposition, especially metal sulfate, on the catalyst, which can be seen from the Fourier infrared spectrum.