Promotional Effects of Ti on a CeO₂–MoO₃ Catalyst for the Selective Catalytic Reduction of NO_x with NH₃

In this study, Ti was doped to CeO 2 –MoO 3 to promote the catalytic performance for the selective catalytic reduction of NO x with NH 3 (NH 3 -SCR). The preparation method for CeMo 0.5 Ti a O x ( a = 0, 1, 2, 5, 10) catalysts was a stepwise precipitation method. When Ti was doped, all of the Ce-Mo-Ti catalysts exhibited remarkably improved NO x conversion and N 2 selectivity than the CeMo 0.5 O x without Ti. The CeMo 0.5 Ti 5 O x with excellent activity in a broad temperature range was selected as an optimal catalyst to investigate the effects of Ti addition. The formation process analysis of the CeMo 0.5 Ti 5 O x showed that, the Mo and Ti species first precipitated together from the mixed solution with the increase of pH, and then Ce species precipitated onto the Mo–Ti precipitates. The obtained catalyst exhibited remarkably facilitated NO x and NH 3 adsorption, enhanced charge imbalance, promoted redox property, and improved surface acidity, which are all important reasons for the excellent catalytic performance of an NH 3 -SCR catalyst.