Synergistic Catalytic Oxidation of Typical Volatile Organic Compound Mixtures on Mn-Based Catalysts: Significant Promotion Effect and Reaction Mechanism

摘要

The miscellaneous volatile organic compounds (VOCs) in industrial flue gas streams usually demonstrate significant mutual inhibition effects, and the behavior of a particular VOC in mixtures is not clear, which hinders the application of catalytic technology. This study examines the catalytic oxidation and mixing effects of representative VOCs in industrial exhausts, consisting of acetone (AC), ethyl acetate (EA), and toluene (Toi), on common Mn-based catalysts (e.g., MnO2 Mn2O3, LaMnO3, and Mn304) by means of intrinsic activity evaluation, coadsorption, VOC temperature-programmed oxidation, in situ diffuse reflectance infrared Fourier transform spectroscopy, and gas chromatography—mass spectrometry. The results showed no inhibiting effect on the conversion of these VOCs when combusted together; instead, a significant mutual promotion effect was found, especially on Toi destruction, with a sharp decrease in the Toi Tso from 214 to 158 °C on Mn02. It is proposed for the first time that the addition of AC/EA in Toi combustion leads to the generation of o/m-methyl phenol, which changes the rate-determining step of the ring-opening process, thus elevating the conversion of Toi together with AC and EA in the mixture at low temperatures.