Investigation of SO2 tolerance of Ce-modified activated semi-coke based catalysts for the NO + CO reaction

Abstract

Activated semi-coke was loaded with Fe–Co mixed oxides and doped with an optimized amount of cerium oxides. This prepared catalyst exhibited excellent NO removal (deNO) activity, and also showed outstanding SO₂ resistance at 250 °C. To understand the SO₂ tolerance mechanism, the catalysts were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, in situ Fourier-transform infrared spectroscopy, H₂-temperature-programmed reduction, and SO₂-temperature-programmed desorption, as well as CO–deNO activity testing under different conditions. The results indicate that the Ce (molar ratio = 0.1) doped onto the Fe–Co binary oxide catalysts would promote the generation of Ce₂(SO₄)₃. This generation could prevent the active metal oxides from being poisoned by SO₂. Furthermore, this kind of sulfate would weaken the interaction between SO₂ and NO, so that the adsorbed NO will have a better opportunity to react with CO.