A General Route to Flame Aerosol Synthesis and In Situ Functionalization of Mesoporous Silica

Abstract

Mesoporous silica is a versatile material for use in catalysis and adsorption in energy, environmental, and medical applications. Here, for the first time, we report a flame aerosol synthesis method for a class of mesoporous silica materials with hollow, amorphous structure, low density, and specific surface area exceeding 1000 m 2 /g. We show its superior performance vs. MCM-41 in properties relevant to water purification, drug carrier, and thermal insulation applications. Moreover, we produced several types of mesoporous silica-supported nano-catalysts by in situ incorporation of active metals. The generality of this method is demonstrated by decorating mesoporous supports with noble metal, transition metal, and metal oxide nanoclusters, including Pt/SiO 2 , Ni/SiO 2 , CrO 3 /SiO 2 , and Co/Al 2 O 3 . As a prototypical application, we demonstrate dry reforming of methane using Ni/SiO 2 , achieving constant 97% CH 4 and CO 2 conversions for more than 200 hours, dramatically outperforming a corresponding MCM-41 supported Ni catalyst. Thus, this work provides a continuous and scalable strategy to produce mesoporous silica nanoshells, and the proposed in situ functionalization mechanism may pave the way to flexible catalysts for a diverse range of reactions.

Challenging thermodynamics: combining immiscible elements in a single-phase nano-ceramic

“…For catalysis applications, we adopted an evaporation-driven micelle self-assembly method to template mesopores in the (Ni 0.07 Al 0.93 )O x in-situ during synthesis, creating mesoporous (Ni 0.07 Al 0.93 )O x nanoshells (Supplementary Figs. 23 , 24 ) 15 . Using this mesoporous metastable binary oxide, we discovered an “encapsulated exsolution” phenomenon, as shown in Fig.…”

“…In this research, we present a general flame aerosol strategy to integrate immiscible elements into a single nano-ceramic phase, based on a modified flame reactor 14 . We also template mesopores in (NiAl)O x solid solution nanoshells through an evaporation-driven micelle self-assembly process 15 and treat this material under reducing conditions to generate active Ni nanoparticles embedded in porous Al 2 O 3 . This resulting nanoconfined structure exhibits ultrahigh activity and stability as a catalyst for CO 2 reforming of methane.…”

Creation of hollow silica-fiberglass soft ceramics for thermal insulation

“…In this study, we adopt a gas-phase synthesis method based on a modified aerosol reactor to produce hollow silica particles with small size and thin, porous shell following an approach we have previously presented. [48] In addition, we also adopt a liquid-phase synthesis route to produce hollow silica particles, using carbon microspheres prepared from glucose by a hydrothermal reaction, as a sacrificial template. [18] Both as-synthesized hollow silicas exhibit much lower thermal conductivity than commercial silica gel.…”

Biocompatible Red Blood Membrane-Carbon Dot Hybrids for Near-Infrared Imaging-Guided Chemotherapy

“…Various nanomaterials (polymer, − liposomes, − carbon, , metal/metal oxide, − and silica − ) have been developed as drug carriers, in which the drug is loaded within the particle or bound to the particle surface. Forming artificial nanocarriers involves complicating the preparation steps and introducing chemical agents that could harm the body .…”