Metal organic framework-derived manganese-cobalt oxide with high SO2 resistance for low-temperature NH3-SCR

Manganese-cobalt oxide catalyst (Mn_xCo_3-xO₄-H) with honeycomb structure was prepared from MnCo-BTC (BTC = 1,3,5-benzenetricarboxylic acid). Its honeycomb structure was inherited from MnCo-BTC with nanoneedle structure and Mn_xCo_3-xO₄-H had a bigger surface area (57.63 m²/g) than that (10.06 m²/g) of Mn_xCo_3-xO₄-C prepared by coprecipitation. The Mn_xCo_3-xO₄-H and Mn_xCo_3-xO₄–C catalysts were tested for low-temperature selective catalytic reduction of NO_x with NH₃ (NH₃-SCR) and compared with Mn_xCo_3-xO₄–C catalyst. As a result, Mn_xCo_3-xO₄–H derived from MnCo-BTC exhibited the superior deNO_x activity, which showed 99% NOx conversion at the existence of 100 ppm SO₂ and 200 °C. To characterize the Mn_xCo_3-xO₄–H and Mn_xCo_3-xO₄–C catalysts, X-ray diffraction (XRD), scanning electron microscopy (SEM) and temperature-programmed desorption experiments of SO₂ (SO₂-TPD) were employed. The SO₂-TPD results showed that Mn_xCo_3-xO₄–H had the weaker SO₂ adsorption than Mn_xCo_3-xO₄–C catalyst, resulting in high SO₂ resistance. Finally, based on the in situ DRIFT experiments, it was demonstrated that SO₂ adsorption on Mn_xCo_3-xO₄–H catalyst was suppressed and the effect of SO₂ on the adsorption of the reactant gases was lower than Mn_xCo_3-xO₄–C catalyst, thus resulting good SO₂ resistance. This work expanded the possible applications of metal organic framework i– the SCR field.

Graphical abstract

It was demonstrated that SO₂ adsorption on Mn_xCo_3-xO₄–H catalyst (a) was suppressed and the effect of SO₂ on the adsorption of the reactant gases was lower than Mn_xCo_3-xO₄–C catalyst, thus resulting good SO₂ resistance.