VOCs abatement using thick eggshell Pt/SBA-15 pellets with hierarchical porosity

• Published in: Catalysis today Vol. 227; pp. 179 - 186
• Main Authors: Usón, Laura, Colmenares, María Gracia, Hueso, José L., Sebastián, Víctor, Balas, Francisco, Arruebo, Manuel, Santamaría, Jesús
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 15.05.2014; Elsevier
• Subjects: Catalysis; Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Hierarchical porosity; Macroporous monolith; Mesoporous silica pellet; Porous materials; Pt catalyst; SBA-15; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; VOCs oxidation; Hierarchical porosity; VOCs oxidation; Mesoporous silica pellet; Macroporous monolith; Pt catalyst; SBA-15; Binary compound; Porous material; Silica; Mesoporosity; Molecular sieve; Heterogeneous catalysis; Oxidation; Porosity; Catalyst; Macroporosity
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2013.08.014

•Mechanically stable 3-D pellets with hierarchical porosity made of SBA-15 silica fibers.•Thick egg-shell distribution of in situ assembled small Pt nanoparticles.•No deactivation observed in the total oxidation of n-hexane after 70h on stream. Mechanically stable 3-D pellets made of mesoporous SBA-15 silica fibers containing highly dispersed platinum nanoparticles have been successfully synthesized with the aid of a sacrificial polyacrylamide network using a gel-casting deposition technique. The pellets exhibit a hierarchical porosity, with spaces of 3 microns among the silica fibers, and a core–shell distribution of Pt, with an outer Pt-rich layer of 450 microns accounting for over 73% of the Pt. Both factors (hierarchical structure and concentration of the catalyst on the outer pellet surface) facilitated reactant access to the catalyst centers, and as a consequence an excellent catalytic activity toward the total oxidation of n-hexane, used as a VOC model. There was no measurable loss of activity after 70h on stream and the subsequent examination of the catalyst revealed that interparticle coalescence of Pt nanoparticles was largely prevented due to the encapsulation of the noble-metal particles within the silica mesochannels.