In situ DRIFTS FT-IR and DFT study on Fe-V-W/Ti removal of NOx and VOCs.

Nitrogen oxides (NOX) and volatile organic compounds (VOCs) are generated during the coal-fired power plant's combustion. They can be simultaneously removed in SCR (selective catalytic reduction) region. Herein, the performance of V-W/Ti and Fe-V-W/Ti synthesized by wet impregnation in removing NOX and VOCs was evaluated. XPS (X-ray photoelectron spectroscopy) result indicated that a redox cycle of Fe2+  + V5+  ⇌ Fe3+  + V4+ could form electron vacancy through electron transfer. Besides, the mechanisms of NH3-SCR and VOCs catalytic oxidation were explored with in situ DRIFTS experience and DFT calculation. On Fe-V-W/Ti, in situ DRIFTS study found more absorption sites of NH3, and different intermediates during simultaneously removal process. DFT calculation demonstrated that absorption energy of O2 was decreased and O = O bond was lengthened with Fe doped. Both V-W/Ti and Fe-V-W/Ti followed the L-H mechanism and shared a common NH3-SCR pathway: [Formula: see text]. However, the bidentate nitrate and monodentate nitrate were also revealed on Fe-V-W/Ti, which combined with NH4+ and decomposed into N2 and H2O, or N2O and H2O, respectively. The detected NH2 species combined with NO on the Fe-V-W/Ti, following the E-R mechanism. As for VOCs, the intermediates of benzene and toluene were revealed by in situ DRIFTS study, and detailed Mars-van Krevelen mechanism was discovered.