Ce(SO4)2/α-Fe2O3 selective catalytic reduction of NOx with NH3: preparation, characterization, and performance

Environ Sci Pollut Res Int. 2022 Dec;29(56):84421-84433. doi: 10.1007/s11356-022-21748-z. Epub 2022 Jul 2.

Abstract

To achieve a low-cost, high-activity denitrification catalyst with excellent water and sulfur resistance, goethite and Ce(SO4)2·4H2O were used to prepare Ce(SO4)2/α-Fe2O3 composite catalyst by the impregnation way and investigated the effect of Ce(SO4)2 on the properties of goethite. Ce(SO4)2/α-Fe2O3 with various preparation conditions for denitration was systematically discussed, and its structure and properties were characterized by XRD, BET, TEM, XPS, H2-TPR, and NH3-TPD methods. The results showed that Ce(SO4)2/α-Fe2O3 over the Ce/Fe molar ratio of 0.02 and calcination temperature of 350 ℃ had excellent catalytic activity, resistance to sulfur, and water properties and stability. When NOx initial concentration was 500 ppm, gas hourly space velocity was 36,000 h-1 and its reaction temperature was 300 ℃; the NOx conversion efficiency was maintained at over 95% along with 300 ppm SO2 and nearly 100% couple with 10% H2O. Its superior performance was mainly attributed to the enhancement of the surface adsorbed oxygen and acidity of α-Fe2O3 by cerium sulfate. The multiple advantages of Ce0.02/α-Fe2O3(350) made it feasible for practical engineering application.

Keywords: Ce(SO4)2; Goethite; Nitrogen oxides; SCR; SO2 tolerance; Stability; α-Fe2O3.

MeSH terms

  • Ammonia* / chemistry
  • Catalysis
  • Oxidation-Reduction
  • Sulfur
  • Water* / chemistry

Substances

  • goethite
  • Ammonia
  • Water
  • Sulfur