Multifunctional Mesoporous Composite Microspheres with Well-Designed Nanostructure: A Highly Integrated Catalyst System

Abstract

The precise control of the size, morphology, surface chemistry, and assembly process of each component is important to construction of integrated functional nanocomposites. We report here the fabrication of multifunctional microspheres which possess a core of nonporous silica-protected magnetite particles, transition layer of active gold nanoparticles, and an outer shell of ordered mesoporous silica with perpendicularly aligned pore channels. The well-designed microspheres have high magnetization (18.6 emu/g), large surface area (236 m(2)/g), highly open mesopores (approximately 2.2 nm), and stably confined but accessible Au nanoparticles and, as a result, show high performance in catalytic reduction of 4-nitrophenol (with conversion of 95% in 12 min), styrene epoxidation with high conversion (72%) and selectivity (80%), especially convenient magnetic separability, long life and good reusability. The unique nanostructure makes the microsphere to be a novel stable and approachable catalyst system for various catalytic industry processes.

Novel synthesis of Au nanoparticles using fluorescent carbon nitride dots as photocatalyst

“…The reduction of 4-NP by NaBH 4 in the presence of noble metal nanoparticles as catalysts has been intensively investigated for the efficient production of 4-AP [44,45]. Therefore, the reduction of 4-NP to 4-AP with an excess amount of NaBH 4 was used as a model system to quantitatively evaluate the catalytic activities of CNDs/ AuNPs.…”

Development of novel supported gold catalysts: A materials perspective

“…Zhao and co-workers fabricated multifunctional mesoporous composite microspheres as a highly integrated catalyst system [60]. In their synthesis, Fe 3 O 4 @SiO 2 microspheres were modified with 3-aminopropyl triethylsilane (APTS), and gold nanoparticles prepared by citrate reduction of HAuCl 4 were immobilized onto the support.…”

Nonstoichiometric Polyelectrolyte Complexes: Smart Nanoreactors for Alloy and Multimetallic Catalyst

“…As shown in Table I, the reaction proceeded very slowly by using any monometallic catalyst, whereas significantly improved by applying bimetallic alloy (aPEC-Au 50 /Ag 50 ) and tri-metallic individual mixture of PEC-Au 50 /Ag 25 /Pd 25 as catalysts. This due to the modification of the electronic structure particularly related to local strain and effective atomic coordination number at the surface in multimetallic materials as well as ligand effect [15]. Finally, metal NP-embedded PECs were used for fabricating intense SERS substrates to detect different molecules.…”