Ta and Mo oxides supported on CeO2-TiO2 for the selective catalytic reduction of NOx with NH3 at low temperature

The SCR of NOx with NH3 is the most efficient technology to reduce the emission of nitrogen oxides from mobile and stationary sources. Ta and Mo catalysts supported on ceria-titania (molar ratio 40:100) were prepared via sol-gel (SG) and wet impregnation (WI) methods and tested for low-temperature NH3-SCR. The preparation methods led to bulk or core-shell catalysts and the effect of these features on performance was investigated in detail. The catalysts were systematically characterized using methods such as ICP-OES, N-2 physisorption (BET), XRD, H-2-TPR, NH3-TPD, XPS, Raman, in situ EPR, and in situ DRIFT spectroscopy. Among all the catalysts, Mo5/Ce40/Ti100 (SG) achieved the highest NOx conversion (8095%) and N-2 selectivity (>97%) over a wide temperature range of 175-400 degrees C. This material outperforms other reported Ce-Ti-based catalysts especially at low temperature. Highly dispersed active species, large BET surface area, high fractions of Ce3+ and enough chemisorbed oxygen species, Lewis acid sites, and good reducibility of the catalyst contribute to the excellent low-temperature DeNO(x) performance of this catalyst. The effect of H2O and SO2 in feed on the activity was investigated. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

NOx reduction using NH3-SCR technology is an efficient method for reducing nitrogen oxide emissions, and the Mo5/Ce40/Ti100 (SG) catalyst supported on ceria-titania shows excellent performance at low temperatures, achieving high NOx conversion rates and N-2 selectivity.