Enhancement of low-temperature NH3-SCR catalytic activity and H2O & SO2 resistance over commercial V2O5-MoO3/TiO2 catalyst by high shear-induced doping of expanded graphite

摘要

In this paper, the preparation of V2O5-MoO3/TiO2-expanded graphite (EG) by different methods was investigated to enhance the H2O resistance in SCR reaction. The catalyst with doping of EG by high shear method showed the best SCR performance. BET, TEM, XPS, H-2-TPR, NH3-TPD and FT-IR were used to analyze the physicochemical characteristics of the prepared catalysts. The results indicated that TiO2 particles were distributed uniformly with EG by high shear method, which enhanced the surface area, increased Bronsted and Lewis acid sites and raised the VO2+ and adsorbed oxygen species on the surface. It was found that even with the addition of H2O (20 %) and SO2 at low temperature, the catalyst doping of EG by high shear method maintained about 90 % NO conversion. In addition, in-situ DRIFT spectra results showed that the NH3-SCR reaction over Cat-1 and Cat-2 followed the E-R and L-H mechanism, and the NH3 and NOx adsorbed species on the surface of Cat-2 possessed higher activity in SCR reaction than Cat-1.