Design strategies for P-containing fuels adaptable CeO2-MoO3 catalysts for DeNO(x): significance of phosphorus resistance and N2 selectivity.

Abstract

Phosphorus compounds from flue gas have a significant deactivation effect on selective catalytic reduction (SCR) DeNOx catalysts. In this work, the effects of phosphorus over three catalysts (CeO2, CeO2-MoO3, and V2O5-MoO3/TiO2) for NH3-SCR were studied, and characterizations were performed aiming at a better understanding of the behavior and poisoning mechanism of phosphorus over SCR catalysts. The CeO2-MoO3 catalyst showed much better catalytic behavior with respect to resistance to phosphorus and N2 selectivity compared with V2O5-MoO3/TiO2 catalyst. With addition of 1.3 wt % P, the SCR activity of V2O5-MoO3/TiO2 decreased dramatically at low temperature due to the impairment of redox property for NO oxidation; meanwhile, the activity over CeO2 and CeO2-MoO3 catalysts was improved. The superior NO oxidation activity contributes to the activity over P-poisoned CeO2 catalyst. The increased surface area and abundant acidity sites contribute to excellent activity over CeO2-MoO3 catalyst. As the content of P increased to 3.9 wt %, the redox cycle over CeO2 catalyst (2CeO2 ↔ Ce2O3 + O*) was destroyed as phosphate accumulated, leading to the decline of SCR activity; whereas, more than 80% NOx conversion and superior N2 selectivity were obtained over CeO2-MoO3 at T > 300 °C. The effect of phosphorus was correlated with the redox properties of SCR catalyst for NH3 and NO oxidation. A spillover effect that phosphate transfers from Ce to Mo in calcination was proposed.

• Authors: Huazhen Chang, Min Tze Jong, Chizhong Wang, Ruiyang Qu, Yu Du, Junhua Li, Jiming Hao
• Journal: Environmental science & technology (Environ Sci Technol) Vol. 47 Issue 20 Pg. 11692-9 (Oct 15 2013) ISSN: 1520-5851 [Electronic] United States
• PMID: 24024774 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Fossil Fuels
• Nitrates
• Oxides
• Water
• Sulfur Dioxide
• molybdenum trioxide
• Phosphorus
• Cerium
• Nitric Oxide
• Cobalt
• ceric oxide
• Ammonia
• Molybdenum
• Titanium
• Nitrogen

Topics

• Adsorption
• Ammonia (isolation & purification)
• Catalysis
• Cerium (chemistry)
• Cobalt (chemistry)
• Denitrification
• Fossil Fuels (analysis)
• Molybdenum (chemistry)
• Nitrates (analysis)
• Nitric Oxide (analysis)
• Nitrogen (chemistry)
• Oxidation-Reduction
• Oxides (chemistry)
• Phosphorus (analysis)
• Spectroscopy, Fourier Transform Infrared
• Sulfur Dioxide (chemistry)
• Titanium (chemistry)
• Water (chemistry)