【摘要】 首次采用低温固相法制备了无载体MnOx催化剂并将其用于NOx的低温NH3选择性催化还原.该催化剂为晶化度极低的混合锰氧化物,部分为粒径40~60 nm的棒状晶体颗粒,其余是更细小的无定形颗粒;催化剂的BET比表面积为150.8m2/g,吸附能力较强,NOx吸附量可达138.27μmol/g.在模拟尾气试验条件下,MnOx催化剂的低温活性很高,80℃时NOx转化率即可达到98.25%;反应产物N2选择性高于96.6%;当通入0.01%SO2和10%H2O后,由于竞争吸附导致NOx转化率有所下降,但仍可保持在70%左右,且不利影响在停止添加SO2和H2O后逐渐消失.更多还原

【Abstract】 A manganese oxide catalyst MnO_x was prepared by the low-temperature solid phase reaction method and used for the low-temperature selective catalytic reduction（SCR） of NO_x with NH₃.The X-ray diffraction results show that MnO_x is a mixture of manganese oxides with poor crystallinity,which contains rodlike crystal particles（40～60 nm） and more fine amorphous particles.The BET specific surface area of the MnO_x is 150.8 m²/g,more great than that of other unsupported catalysts ever reported,and thus its capability of adsorption is superior.In our experiments,the amount of adsorbed NO_x reaches 138.27 μmol/g.The SCR results show that the MnO_x is an efficient catalyst for the SCR of NO_x at low temperature.A NO_x conversion of 98.25% and product selectivity for N₂ of 96.6% was obtained at 80 ℃.The addition of 0.01%SO₂ and 10%H₂O weakens the adsorption of NO_x by competition on the catalyst surface,which decreases the NO_x conversion to 70% after reaction for 2.5 h.The catalyst activity can be recovered after the removal of SO₂ and H₂O.更多还原