The effects of calcination atmosphere on the catalytic performance of Ce-doped TiO2 catalysts for selective catalytic reduction of NO with NH3

A series of well-reported Ce-x-Ti catalysts with a low content of Ce species were synthesized by a sol-gel method. The aim of this study was to investigate the influence of different calcination atmospheres on the formation of the Ce-O-Ti structure that comprises active sites for the selective catalytic reduction (SCR) of NO by NH3. Catalytic activity tests showed that the Ce-x-Ti-N (calcined under a nitrogen atmosphere) catalysts exhibited a significantly higher NO removal efficiency than Ce-x-Ti-A (calcined under air). Characterization results confirmed that more Ce species could incorporate into the TiO2 lattice when calcined under a nitrogen atmosphere, thus, more Ce-O-Ti structures were obtained over the Ce-x-TiN surface. This improved the NH3 adsorption and electron transfer from Ti to Ce. Therefore, N-2 calcination increased the acid sites and improved the redox ability for Ce-x-Ti-N catalysts. In addition, it was found that the redox ability was the critical factor, which effectively promoted the low temperature SCR performance. Amongst the Ce-x-Ti-N catalysts, Ce-5-Ti-N revealed the best SCR activity, catalytic stability and resistance to H2O and SO2. This study demonstrated the feasibility of N-2 calcination in the syntheses of doped SCR catalysts and also explored the SCR reaction mechanism over the well-reported Ce-x-Ti catalysts. We expect that this study could shed some light on the development of feasible preparative routes for the syntheses of Metal-Ti catalysts for SCR application.