Challenging design of highly active Pt/CeO2–TiO2/ZSM-5 catalysts for VOCs low-temperature removal

Abstract

Four Pt/CeO2–TiO2/ZSM-5 catalysts with different Pt species dispersion states and acidic properties were designed, and key factors affecting the oxidation activity of various VOCs (benzene, DCE, ethyl acetate and acetonitrile as typical organic compounds of aromatic hydrocarbon and halogen/oxygen/nitrogen-containing VOCs, respectively) were identified in the present work. The strength of the acid and oxidation sites on the surface of catalysts and their synergistic interaction play a crucial role. Highly dispersed Pt species and its strong redox ability promote low-temperature oxidation of benzene. A synergistic interaction between the acid and oxidation sites is required to achieve high DCE oxidation activity. An abundance of surface acid sites (particularly strong acid sites) favors the adsorption and dechlorination to form vinyl chloride of DCE, and the strong redox ability of oxidation sites would accelerate the deep oxidation of intermediates (such as vinyl chloride and acetic acid, etc.). For ethyl acetate or acetonitrile oxidation, the strong acidic property of the catalyst plays a prior role for their catalytic oxidation, which facilitates the low-temperature hydrolysis of ethyl acetate or acetonitrile. This work provides a significant thought to design and synthesize high activity catalysts for low-temperature oxidation of various VOCs pollutants.