Performance of Mn-Ce co-doped siderite catalysts in the selective catalytic reduction of NO_x by NH₃

Siderite, rich in the transition elements, is an idea material to prepare the catalysts for the selective catalytic reduction (SCR) of NO_x by NH₃. In this work, siderite was doped with Mn and Ce and the performance of Mn-Ce co-doped siderite catalysts in the removal of NO_x (de-NO_x) by SCR with NH₃ was then investigated. The results illustrate that FeCO₃ as the main component of siderite can be converted into Fe₂O₃ by calcination at 450℃. The doping of siderite with Mn and Ce can enhance the surface area and acidity of siderite and reduce the thermal stability of ammonium sulfate formed on the catalyst surface. As a result, the Mn-Ce co-doped siderite catalysts exhibit high efficiency in the de-NO_x by SCR and high resistance against sulfur. Over the 3%Mn1%Ce-siderite catalyst, high NO_x conversion (>90%) is achieved in the temperature window of 180-300℃; moreover, the NO_x conversion remains above 75% even after introducing SO₂ for 7.5 h.