Selective and regular localization of accessible Pt nanoparticles inside the walls of an ordered silica: Application as a highly active and well-defined heterogeneous catalyst for propene and styrene hydrogenation reactions
Type
ArticleAuthors
Boualleg, MalikaNorsic, Sébastien
Baudouin, David
Sayah, Reine
Quadrelli, Elsje Alessandra
Basset, Jean-Marie

Candy, Jean Pierre
Délichère, Pierre
Pelzer, Katrin
Veyre, Laurent
Thieuleux, Chloé
KAUST Department
Chemical Science ProgramKAUST Catalysis Center (KCC)
Physical Science and Engineering (PSE) Division
Date
2011-12Permanent link to this record
http://hdl.handle.net/10754/561947
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We describe here an original methodology related to the "build-the-bottle-around-the-ship" approach yielding a highly ordered silica matrix containing regularly distributed Pt nanoparticles (NPs) located inside the silica walls, Pt@{walls}SiO2. The starting colloidal solution of crystalline Pt nanoparticles was obtained from Pt(dba)2 (dba = dibenzylidene acetone) and 3-chloropropylsilane. The resulting nanoparticles (diameter: 2.0 ± 0.4 nm determined by HRTEM) resulted hydrophilic. The NPs present in the THF colloidal solution were incorporated inside the walls of a highly ordered 2D hexagonal mesoporous silica matrix via sol-gel process using a templating route with tetraethylorthosilicate, TEOS, as the silica source, and block copolymer (EthyleneOxide) 20(PropyleneOxide)70(EthyleneOxide)20 (Pluronic P123) as the structure-directing agent. Low-temperature calcination of the crude material at 593 K led to the final solid Pt@{walls}SiO2. Characterization by IR, HRTEM, BF-STEM and HAADF-STEM, SAXS, WAXS, XRD, XPS, H2 chemisorption, etc. of Pt@{walls}SiO2 confirmed the 2D hexagonal structuration and high mesoporosity (870 m2/g) of the material as well as the presence of stable 2-nm-sized crystalline Pt(0) NPs embedded inside the walls of the silica matrix. The material displayed no tendency to NPs sintering or leaching (Pt loading 0.3 wt.%) during its preparation. Pt@{walls}SiO2 was found to be a stable, selective and highly active hydrogenation catalyst. The catalytic performances in propene hydrogenation were tested under chemical regime conditions in a tubular flow reactor (278 K, propene/H2/He = 20/16/1.09 cm3/min, P tot = 1 bar) and were found superior to those of an homologous solid containing Pt NPs along its pore channels Pt@{pores}SiO2 and to those of a classical industrial catalysts Pt/Al2O3, (TOF = 2.3 s-1 vs. TOF = 0.90 and 0.92 s-1, respectively, calculated per surface platinum atoms). Pt@{walls}SiO2 also catalyzes fast and selective styrene hydrogenation. A material containing by design Pt NPs both in its walls and in its pores, Pt@{walls + pores}SiO2, is also described. © 2011 Elsevier Inc. All rights reserved.Citation
Boualleg, M., Norsic, S., Baudouin, D., Sayah, R., Quadrelli, E. A., Basset, J.-M., … Thieuleux, C. (2011). Selective and regular localization of accessible Pt nanoparticles inside the walls of an ordered silica: Application as a highly active and well-defined heterogeneous catalyst for propene and styrene hydrogenation reactions. Journal of Catalysis, 284(2), 184–193. doi:10.1016/j.jcat.2011.09.003Publisher
Elsevier BVJournal
Journal of Catalysisae974a485f413a2113503eed53cd6c53
10.1016/j.jcat.2011.09.003