Oxygen-Functionalized Activated Carbon Supported Vanadia Catalysts : Unexpected Improvement in Low-Temperature Nh3-Scr Performance

A series of oxygen-functionalized activated carbon (AC) supported vanadia catalysts were first synthesized for the low-temperature selective catalytic reduction (SCR) of NOx with NH3 via wet oxidation method using ammonium persulfate ((NH4)2S2O8) as an oxidant. The physicochemical properties of samples were characterized by BET, SEM, XRD, Raman, XPS, H2-TPR, NH3-TPD. (NH4)2S2O8 modification promoted redox property, surface acidity of V/OAC2-60-3 and produced abundant reactive oxygen species, which enhance the catalytic activity significantly. Especially, (NH4)2S2O8 activation promoted a high V4+/V5+ ratio on V/OAC2-60-3. The in-situ DRIFTs experiments demonstrated that V/OAC2-60-3 could absorb more NH3 species on Lewis acid sites and both the Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) mechanisms were present on V/OAC2-60-3. Based on the results in this work, a promotional mechanism for the low-temperature NH3-SCR was proposed over V/OAC2-60-3