Insight into the effect of Nb modification towards the wide-temperature NH3-SCR performance of ceria catalyst

With the increasingly stringent requirements for the treatment of industrial nitrogen oxides (NO x ), ammonia selective catalytic reduction (NH 3 -SCR) has emerged as the most widely adopted denitrification technology in industrial settings. A series of CeNbO x nano-catalyst with varying Nb compositions were synthesized via the solvothermal method for NH 3 -SCR. All the CeNbO x samples presented considerable NO x conversion, exceeding 80% within a broad temperature window of 200-350°C. In addition, the optimal sample shown high stability and strong resistance to SO 2 /H 2 O at 225°C. The influence of Nb element on structural properties of the CeNbO x samples was investigated and elucidated using multiple characterization techniques. The NH 3 -SCR process was further studied by in situ infrared Fourier transform spectroscopy ( in situ FTIR ), temperature-programmed reduction with H 2 (H 2 -TPR) and X-ray photoelectron spectroscopy (XPS), which revealed that the improved NO x conversion can be attributed to the role of Nb in suppressing the crystal growth of CeO 2 , promoting the adsorption of oxygen species, increasing the distribution of Ce and improving the redox ability.