Carbon Spheres with Controllable Silver Nanoparticle Doping

Abstract

We report a facile method to dope submicrometer carbon spheres with Ag nanoparticles (NPs) to fabricate Ag-NP/C composites via microwaving suspensions of nanoporous carbon spheres in aqueous Ag(NH3)2 + solutions with poly(N-vinylpyrrolidone) as reducer. The composite particles are synthesized in high yield within a short reaction time, and the size, number density, and to some extent even the locations of NPs in/on the carbon spheres can be controlled by adjusting reaction parameters. The controllability is discussed based on the experimental results from transmission electron microscopy, X-ray photoelectron spectroscopy depth profiling, and X-ray diffraction. By controlling the Ag doping, the composite spheres exhibit not only a tunable plasmon resonance shift but also an excellent catalytic activity toward the reduction of 4-nitrophenol by sodium borohydride.

Eco-friendly green synthesis of silver nanoparticles using salmalia malabarica: synthesis, characterization, antimicrobial, and catalytic activity studies

“…These metal nanoparticles exhibit size-dependent optical and electronic properties. Among several nanomaterials of recent interest, the most prominent one is that of silver (AgNPs) due to its unique size and shape-dependent optical, electronic, and catalytic properties (El-Sayed 2001;Tang et al 2010;Chau and Yeh 2011). Silver makes it an excellent choice for numerous roles in the medical field for antifungal, antioxidant, and anti-inflammatory effects (Kenneth et al 2009;Sang et al 2012;Amit Kumar et al 2012).…”

Reduction of 4‐Nitrophenol as a Model Reaction for Nanocatalysis

“…Th e NPs were recovered, washed and recycled 5 times, which exceeds the performance of homogeneous catalysts such as DENs. [101,102] Metal NPs deposited on the outside of silica or carbon spheres are oft en characterized by non-uniform distribution, low density and poor longterm stability. As such, Tang et al tried to embed Ag NPs (10 nm) inside porous carbon spheres (CSs) to enhance the stability, lower the toxicity and alter the electro-optical properties resulting from matrix embedding and the diff erent collective interactions of the NPs [101].…”

“…Furthermore, their large-scale application is hindered by a reduction in catalytic activity due to particle aggregation. To overcome these disadvantages, metal nanocomposite catalysts have been immobilized onto solid supports such as inorganic oxide [89,90,93,100,106,109,110], ion exchange resins [70,71,87], alumina [88,108], titania [11], polymer microspheres [78,91,[97][98][99], polystyrene [5,72,76,77,79,92,96,104,105], nanotubes [103], carbon spheres [101,102], and biomolecule beads [58]. Th ese supports must not take part in the catalytic mechanism, i.e., they must be inert.…”

“…43 TEM images of the products obtained under various reaction conditions[101]. (Reprinted with permission from[101]; Copyright 2010, American Chemical Society.…”

Study of Preparation, Growth Mechanism and Catalytic Performance of Carbon Based Embedded Silver Nano Composite Materials

“…Compared with other techniques, the hydrothermal reduction method has mild reaction conditions, low energy consumption and simple operation, which can achieve the morphology control of the composite materials. For instance, hydrothermal carbon spheres with metal nanoparticles doping are attracting increased interest [9][10][11] because hydrothermal carbonaceous materials own abundant hydroxyl groups, which can help to load with noble-metal nanoparticles and make them possible to integrate differently sized noble-metal nanoparticles with layered structures [12]. However, these noble-metal nanoparticles were loaded on the CSs surface by in-situ reduction after the as-prepared CSs were dispersed in AgNO 3 aqueous solutions, which can not to solve the problem of silver nanoparticles prone to be oxidized easily.…”