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

- Highly ordered mesoporous WO3(χ)-CeO2 have been successfully synthesized.
- The ordered mesoporous WO3(χ)-CeO2 shows superior low temperature catalytic activity and N2 selectivity.
- The ordered mesoporous WO3(χ)-CeO2 have stronger Lewis acid sites and higher Ce3+ concentration.
- The ordered mesoporous WO3(χ)-CeO2 also presented excellent H2O resistance and alkali metal resistance.

To eliminate nitrogen oxides (NOx), a series of highly ordered mesoporous WO3(χ)-CeO2 nanomaterials (χ 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, H2-TPR, NH3-TPD and in situ DRIFTS. It can be found that all of the prepared mesoporous WO3(χ)-CeO2 (χ = 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 °C to 350 °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, H2-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 N2 selectivity, were systematically studied, indicating that the synthesized mesoporous WO3(1)-CeO2 has great potential for industrial applications.

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