Effect of fluorine additives on the performance of amorphous Ce-Ti catalyst and its promotional progress on ozone for NOX (x = 1, 2) removal at low temperature

Abstract

Nanostructured F doped cerium and titanium mixed oxide catalyst (CeTiF) and cerium and titanium mixed oxide catalyst (CeTi) were prepared by co-precipitation method. The F is for the first time to be doped into CeTi as the ozonation catalyst. Compared to CeTi, the catalyst of CeTiF exhibited a better catalytic activity, yielding 83% NOx (x=1, 2) conversion at 40°C. In order to investigate the effect of F on CeO2-TiO2 catalysts for the catalytic ozonation of NOx (x=1, 2), the catalysts were characterized by XRD, PL spectra, Raman spectra, XPS, TGA, NH3-TPD and FTIR techniques. The CeTiF exhibits higher catalytic activity than CeTi, which is found that it presents linear relationship with the OH radical concentration. The doping of F does substitute the O in CeOTi, TiOTi or CeOCe linkage bonds to produce more oxygen vacancies, and slightly enhances the BET surface area and hydrophilicity, which promote the chemisorption of H2O to form surface OH, and benefiting the O3 adsorption on the surface OH, thus promoting the production of OH, further improving the catalytic performance. These oxygen vacancy and surface hydroxyl groups play a critical role in the OH production for NOx removal.