Macroporosity-Heightened Mass Transfer Enabling Complete Benzene Oxidation over Pt/SiO₂ Catalyst

Mass transfer governs the overall catalytic performance of heterogeneous catalysts considerably; however, this fundamental research has often been ignored. Here, macroporous SiO₂-supported Pt nanoparticle (Pt/SiO₂-M) and mesoporous SiO₂-supported Pt nanoparticle (Pt/SiO₂-m) catalysts were specifically fabricated by a facile thermal reduction step to engineer the resultant Pt nanoparticles showing similar physiochemical properties while possessing completely different porous microstructures exclusively originating from SiO₂ supports. On this basis, a platform to explore the crucial mass transfer difference affecting catalytic activity is then established by systematically practicing industry-important benzene oxidation measurements. State-of-the-art characterization techniques confirmed that all of the as-synthesized Pt/SiO₂ catalysts indeed exhibited almost identical Pt sites, excluding catalytic discrepancies raised from Pt nanoparticles. Importantly, Pt/SiO₂-M displayed complete benzene oxidation capabilities at a lower temperature than that for Pt/SiO₂-m, accrediting to the macroporosity-induced faster desorption rate of H₂O and CO₂, thus making it capable of enhancing the high utilization of Pt sites. This work highlights the importance of improving mass transfer capability toward supported nanoparticulate catalysts, demonstrating the significance of designing novel macroporous supports for industry-important catalysis implications.