ZrO<sub>2</sub> Modified MnO<sub><i>x</i></sub>/Attapulgite Catalysts for NH<sub>3</sub>-SCR of NO at Low Temperature

A series of Zirconium modified MnOx/Attapulgite (aZr–Mn/ATP) catalysts were synthesized by sol–gel method and evaluated for their performance in the low-temperature NH3-SCR of NO and resistance to sulfur dioxide (SO2). It was found that the NO conversion of Mn/ATP catalyst significantly improved after adding Zr. Among the catalysts investigated, the 4%Zr–Mn/ATP catalyst exhibited the highest catalytic activity, 96% NO conversion at 200°C, almost 100% N2 selectivity in the whole test temperature range and good resistance to SO2. The properties of catalysts were characterized by XRD, FTIR spectra, SEM and N2 adsorption. In the catalyst, ATP is the support which supplies high surface areas, manganese (Mn3O4 and MnO2) as the main active component plays an important role for NO reduction and zirconium (ZrO2) acts as the auxiliary catalyst which can improve the diffusion of Mn, boost the low-temperature reduction performance and enhance the N2 selectivity of the catalyst.