Entrapment of metal nanoparticles within nanocages of mesoporous silicas aided by co-surfactants

Abstract

We demonstrated an efficient approach for in situ encapsulation of metal nanoparticles (NPs) into nanocages of mesoporous silicas using a co-surfactant as the transportation medium. By using this approach, colloidal Pt and Au NPs were successfully encapsulated into the nanocages of cagelike mesoporous silicas (CMS) and FDU-12 using co-surfactants butanol and mesitylene (TMB) as the transportation medium, respectively. The prepared Pt/CMS catalysts are active and highly selective in the hydrogenation of chloronitrobenzene (CNB) to the corresponding chloroaniline (CAN). The catalyst prepared by the in situ method is superior to the catalyst prepared by the traditional solution impregnation method. This work provides a new approach for the synthesis of the mesoporous materials with encapsulated metal NPs.

Controlled deposition of titanium oxide overcoats by non-hydrolytic sol gel for improved catalyst selectivity and stability

“…To obtain the targeted reactivity, we focused on the direct condensation of metal halide TiCl 4 with titanium alkoxides, while screening various reaction conditions. We achieved optimal control on the condensation for the reaction between TiCl 4 and Ti( i OPr) 4 (titanium isopropoxide). Fast ligand recombination is known to occur in metal halides and metal alkoxides mixtures [41] but no condensation was observed at room temperature between TiCl 4 and Ti( i OPr) 4 , even after several days.…”

“…Here, we present a technique for the controlled deposition of TiO 2 overcoats based on non-hydrolytic sol-gel chemistry. Continuous injection of Ti( i PrO) 4 and TiCl 4 mixtures led to the formation of conformal TiO 2 overcoats with a growth rate of 0.4 nm/injected monolayer on several materials including high surface area SBA-15. Deposition of TiO 2 on SBA-15 generated mediumstrength Lewis acid sites, which catalyzed 1-phenylethanol dehydration at high selectivities and decreased deactivation rates compared to typically used HZSM-5.…”

“…Deposition of thin metal oxide layers on the surface offers the opportunity to create optimal environment on the material surface [1][2][3][4][5][6]. Multiple studies demonstrate that liquid phase sol-gel based techniques can be used for the controlled growth of oxide films [7][8][9][10][11].…”

Ultrasmall single micelle@resin core–shell nanocarriers as efficient cargo loading vehicles for in vivo biomedical applications

“…To identify the suitable synthesis conditions for the fabrication of Micelle Fx @RFR core-shell NCs, different synthesis parameters were adopted, such as different ammonium contents (0.05 and 0.16 M), temperatures (60 and 95 1C) and precursor concentrations (42,49,55 and 65 mM for resorcinol and 84, 98, 110 and 130 mM for formaldehyde respectively). One parameter was changed each time, while the other parameters and procedures were the same as those for the Micelle F108 @RFR core-shell NCs.…”

Carboxylic acid Functionalized Cage‐Type Mesoporous Silica FDU‐12 as Support for Controlled Synthesis of Platinum Nanoparticles and Their Catalytic Applications

“…Moreover, leaching of the NPs always takes place during the catalytic process. Alternately, 3D cubic mesoporous silicas such as SBA‐16, MCM‐48, and FDU‐12 are believed to be better supports for the growth of metal NPs and/or preventing aggregation, as their structures are more resistant to pore blocking and thus offer more adsorption sites and faster diffusion of reactants. The mesoporous architecture of FDU‐12, with face‐centered cubic ( Fm 3 m ) symmetry, is composed of spherical nanocavities that are linked together by very short nanochannels or windows.…”