Low-temperature indoor VOC oxidation over Pt catalysts: Interplay between zeolite acidity and framework architecture

In this study, platinum nanoparticles (0.5 wt%, <4 nm) were deposited on microporous ZSM-5 zeolites with different SiO2/Al2O3 molar ratios and on mesoporous SBA-15 silica to investigate the influence of support properties on indoor VOC oxidation under mild conditions. TEM, CO chemisorption and XPS confirmed uniform particle size, high metal dispersion and predominantly metallic Pt on all catalysts, ensuring a direct comparison of support-dependent effects. Catalytic activity was evaluated for the oxidation of CO, ethylene and toluene at an indoor-relevant concentration of 100 ppm in air. CO oxidation started at room temperature and was mainly governed by exposed Pt sites, whereas support characteristics may contribute to the observed differences in low-temperature activity. For ethylene and toluene oxidation, Pt/ZSM-5 catalysts showed improved performance compared with Pt/SBA-15, suggesting that the physicochemical properties of the zeolitic support, including acidity and pore architecture, influence reactant adsorption and accessibility to catalytic sites. These findings provide useful guidelines for the design of efficient low-loading Pt-based catalysts for indoor air purification technologies.