The selective catalytic reduction reaction and mechanism of citric acid
modified the CeO2-WO3/TiO2 catalyst
Abstract
In this study, the CeO2-WO3/TiO2-n catalyst was synthesized by
co-precipitation method with citric acid and the selective catalytic
reduction (SCR) performance of citric acid modified CeO2-WO3/TiO2
catalyst was studied. The results demonstrated that compared with
CeO2-WO3/TiO2 catalyst, CeO2-WO3/TiO2-6% catalyst has been widened
about 30°C in the temperature range of 80% and 90%, respectively, and
the highest denitration efficiency was 98.83% at 350°C. Additionally,
citric acid formed complex with WO3 and CeO2 and three carboxylic acid
groups can improve the stability of WO3 to inhibit the growth of TiO2
and CeO2 crystallites, thus promoting the dispersion of CeO2 and the
formation of Ce-O-W solid solution. Furthermore, the strong interaction
between CeO2 and WO3 in CeO2-WO3/TiO2-6% catalyst will release more Oα
and Ce3+. Citric acid promoted the interaction of unsaturated W atoms
and hydroxyl groups adsorbed on unsaturated W atoms, thus providing more
Lewis and Brönsted acid sites on the catalyst surface