Dynamic Evolution of Active Sites Governing the Synergistic Oxidation of Binary Benzene–Ethyl Acetate Mixtures Over Pt/Al 2 O 3 Catalyst

Catalytic oxidation is widely recognized as an efficient strategy for the abatement of industrial volatile organic compounds (VOCs). However, the mechanistic understanding of catalytic oxidation in the presence of multiple pollutants under practical operating conditions remains limited and inconclusive. Herein, the interaction between benzene and ethyl acetate (EA) during their co-oxidation over a Pt/Al₂O₃ catalyst is systematically evaluated. Results show that the oxidation activity of benzene is inhibited by EA, while the oxidation activity of EA is promoted by benzene under mixed-pollutant conditions. Various characterization techniques, including coadsorption experiments, temperature-programmed desorption, and in situ diffuse reflectance infrared Fourier transform spectroscopy, reveal that competitive adsorption is the primary cause of the decreased activity in benzene oxidation. Alternatively, although the presence of benzene inhibits EA adsorption, the superior performance of benzene oxidation results in the preferential consumption of adsorbed oxygen on Pt sites. This, in turn, promotes the adsorption of acetic acid─a hydrolysis product of EA─resulting in an overall enhancement in its oxidation activity. This oxygen-scavenging effect exerts a universal promotional influence on the oxidation of a mixture of aromatic hydrocarbons and various oxygen-containing VOCs. This study elucidates the critical role of the dynamic evolution of active sites during the oxidation of mixed VOCs and provides guidance for the design of high-performance catalysts for the catalytic oxidation of multicomponent VOCs.