ZSM-5-supported V-Cu bimetallic oxide catalyst for remarkable catalytic oxidation of toluene in coal-fired flue gas

Abstract A close-coupled catalytic oxidation module after the NH3-SCR section has been constructed that employs catalytic materials to achieve high-efficiency oxidation of toluene (a surrogate for VOCs stemming from coal combustion) during flue gas purification. The V-Cu bimetallic bifunctional catalyst supported on ZSM-5 zeolite (V-Cu/ZSM-5) not only efficiently removed VOCs but also tolerated to complex flue gas. The catalytic material that removed the toluene was easily fabricated via the impregnation method. Results showed that, compared with single metal-supported catalysts, the V-Cu/ZSM-5 catalyst exhibited enhanced performance. This superior performance was attributed to improved reducibility at lower temperatures, higher electron transfer efficiency, more abundant Oα species and lower C7H8 activation temperature. The material also exhibited excellent flue gas tolerance and COx selectivity. The suppression mechanism of VOCs oxidation under complex coal-fired flue gas has been elucidated for the first time. There was competitive adsorption between the toluene and NH3 and/or NO. SO2 in the flue gas would cause chemical poisoning of the catalyst. Finally, in-situ DRITFS studies gave insights on the reaction mechanism. In short, this work provides new ideas and strategies for removing VOCs from complex coal-fired flue gas.