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

Area of Science:

• Materials Science
• Chemical Engineering
• Catalysis

Background:

• Mass transfer significantly impacts heterogeneous catalyst performance but is often overlooked in fundamental research.
• Designing catalysts with controlled porous structures is crucial for optimizing reaction kinetics and efficiency.

Purpose of the Study:

• To investigate the effect of support porosity on catalytic activity by comparing macroporous and mesoporous silica-supported platinum nanoparticle catalysts.
• To establish a platform for studying mass transfer effects in industry-relevant catalytic reactions.

Main Methods:

• Fabrication of macroporous (Pt/SiO2-M) and mesoporous (Pt/SiO2-m) silica-supported platinum nanoparticle catalysts via thermal reduction.
• Characterization of catalysts using state-of-the-art techniques to confirm similar Pt sites.
• Performance evaluation through benzene oxidation measurements.

Main Results:

• Synthesized catalysts exhibited nearly identical platinum sites, isolating the effect of support microstructure.
• Pt/SiO2-M demonstrated superior benzene oxidation activity at lower temperatures compared to Pt/SiO2-m.
• Enhanced catalytic performance of Pt/SiO2-M was attributed to faster desorption of water and carbon dioxide due to macroporosity.

Conclusions:

• Macroporous supports significantly enhance catalyst performance by improving mass transfer, specifically product desorption rates.
• Designing supports with optimized porosity is critical for maximizing the utilization of active sites in supported nanoparticulate catalysts.
• This research underscores the importance of considering mass transfer limitations in the development of advanced catalysts for industrial applications.