Efficient NH3-SCR removal of NOx with highly ordered mesoporous WO3(χ)-CeO2 at low temperatures

To eliminate nitrogen oxides (NOx), a series of highly ordered mesoporous WO3(chi)-CeO2 nanomaterials (chi represents the mole ratio of W/Ce) were synthesized by using KIT-6 as a hard template, which was used for selective catalytic reduction (SCR) to remove NOx with NH3 at low temperatures. Moreover, the nanomaterials were characterized by TEM, XRD, Raman, XPS, BET, H-2-TPR, NH3-TPD and in situ DRIFTS. It can be found that all of the prepared mesoporous WO3(chi)-CeO2 (chi = 0, 0.5, 0.75,1 and 1.25) showed highly ordered mesoporous channels. Furthermore, mesoporous WO3(1)-CeO2 exhibited the best removal efficiency of NOx, and its NOx conversion ratio could reach 100% from 225 degrees C to 350 degrees C with a gas hourly space velocity of 30 000 h(-1), which was due to higher Ce3+ concentrations, abundant active surface oxygen species and Lewis acid sites based on XPS, H-2-TPR, NH3-TPD and in situ DRIFTS. In addition, several key performance parameters of mesoporous WO3(1)-CeO2, such as superior water resistance, better alkali metal resistance, higher thermal stability and N-2 selectivity, were systematically studied, indicating that the synthesized mesoporous WO3(1)-CeO2 has great potential for industrial applications. (C) 2016 Elsevier B.V. All rights reserved.