Structure Control Of V₂O₅/CNFs/Al₂O₃-CC Catalyst And Its NO Catalytic Rerducation At Low Temperature

Carbon nano fibers (CNFs) is a new carbon material with unique quasi-one-dimensional fibrous structure. Due to its controllable microstructure, large specific surface area, high mechanical strength, strong interface effect, it has a wide application prospect on catalyst field. V2O5/CNFs catalyst is able to overcome the SO2 poisoning in selective catalytic reduction (SCR).This work invented a new type of SCR catalyst, V2O5/CNFs/Al2O3-Coated Cordierite (V2O5/CNFs/Al2O3-CC), and evaluated its NO catalytic reduction activity at low temperature. The main conclusions are as followings:(1) The alumina coating on honeycomb cordierite (Al2O3-CC) has high bonding strength. Al2O3-CC is a good catalyst matrix material.(2) The amount of CNFs growth is almost a positive correlation linear relationship with the amount of NiO loadings. The amount of NiO loadings is also the key to CNFs/Al2O3-CC mechanical strength. The CNFs growth time (30 minutes) can ensure the uniformity of CNFs growth on Al2O3-CC. CNFs/Al2O3-CC start to lose weight over 400℃in the air, so it is perfectly suited as the catalyst support below 300℃.(3) After CNFs growth, NiO still lies in CNFs/Al2O3-CC. It must be removed by acid treatment. Acid treatment can also increase the amount of oxygen functional groups on CNFs surface. Except for little mass loss, acid treatment has no effect to CNFs contents and the heat-resistant property of CNFs/Al2O3-CC.(4) The combination form of vanadium is V2O5 on V2O5/CNFs/Al2O3-CC. It disperses widely on CNFs surface, achieving a molecular level.(5) In the reaction system without SO2, the catalytic activity of V2O5/CNFs/Al2O3-CC is raising with the increasing of the temperature and the amount of CNFs growth and V2O5 loading. The efficiency of NO reduction can reach up more than 95%.(6) In the reaction system with SO2, the catalytic activity of V205/CNFs/Al203-CC is also raising with the increasing of the temperature and the amount of CNFs growth and V2O5 loading. But, compared with the reaction system without SO2, for 1.0%V2O5/CNFs/Al2O3-CC catalyst with 5.7%,7.6% and 9.1% CNFs, S02 has negative effect to NO reduction at 150℃-200℃; SO2 has positive effect to NO reduction at 220℃-250℃. For the 1.0%V2O5/12.5%CNFs/Al2O3-CC catalyst, the positive effect from SO2 needs higher temperature.