In Situ Synthesis of Highly Dispersed Silver Nanoparticles on Multiwalled Carbon

Abstract

Since their discovery, 1 carbon nanotubes (CNTs) have been continuously attracting extensive interests in many areas of science and technology and have been the focus of current research for many years due to their unique structure-dependent optical, electrical, and mechanical properties. Recently, silver decorated CNT hybrids are increasingly attracting extensive attention due to their potential applications as catalyst, 2 broad-band optical limiters, 3 electrodes, 4 and advanced materials.5 Hybrid systems of nanomaterials may have collective properties that are drastically different from a simple combination of individual components. Therefore, many approaches and strategies, including the solid-state reaction,6 γ-irradiation, 7 and other synthesis routes, [8][9][10][11][12][13][14] have been attempted to attach silver nanoparticles (NPs) or nanoclusters on the functionalized CNTs. To prepare well-constructed silver NP-decorated CNTs, however, a simple and effective route is still more desired.Here we report on a novel and facile wet-chemical method for the synthesis of silver NP-CNT assemblies, that is based on traditional coordination chemistry and can be generally applied to common metal elements. Key to the synthesis lies in the 3-aminopropyltriethoxysilane (APS)-mediated loading of silver precusors on the functionalized CNTs. The full procedure for preparing silver NP-CNT composites is shown in Figure 1.MWCNTs were obtained from NTP (Shenzhen, China). Lithium aluminum hydride (LiAlH 4 , 95%) and APS (99%) were purchased from Aldrich. Other chemicals used were all analytical pure and purchased from Sinopharm Chemical Reagent Co. Ltd. (Shanghai, China). Surface treatment of MWCNTs followed a standard route. In brief, MWCNTs were reuxed in mixture acids made of nitric acid and sulfuric acid for 2 h to give carboxyl groups modified MWCNT (MWCNT-COOH), 15 followed by reaction with LiAlH 4 in dry tetrahydrofuran (THF) at room temperature for 12 h, resulting in hydroxyl group functionalized MWCNT (MWCNT-OH). The (MWCNT-O-) 3 -Si(CH 2 ) 3 NH 2 intermediate was realized via covalent coupling of MWCNT-OH and an excess of APS in anhydrous toluene at 120 o C for 24 h under the protection of argon (Ar). The (MWCNT-O-) 3 Si(CH 2 ) 3 NH 2 -Ag + complex was obtained by reaction between (MWCNT-O-) 3 Si(CH 2 ) 3 NH 2 and 1.0 mol/L AgNO 3 solution at room temperature for 2 h. The final silver NP loaded MWCNT (MWCNT-O-) 3 Si(CH 2 ) 3 -NH 2 Ag) hybrids were fabricated via in situ reduction with sodium borohydride (NaBH 4 ). The as-prepared mixtures were fully washed with distilled water and absolute ethanol for several times. Finally, the products were collected by centrifugation and the precipitate was dried at 60 o C in vacuum for 10 h.The morphology and dimension of the product were observed by transmission electron microscopy (TEM), which was taken on a Hitachi Model H-600 electron microscopy using an accelerating voltage of 100 kV. The crystalline structure of the sample was characterized by X-ray diffractometer equipped...

Synthesis and Characterization of Silver Nanoparticle‐Multiwalled Carbon Nanotube Composites

“…Several methodologies have been developed to obtain silver nanoparticle-CNT composites, such as solid-state reaction, thermal evaporation, surface chemical reduction of the metal salt, and wet chemical routes [10][11][12][13][14][17][18][19][20] promoting either covalent or noncovalent functionalization between NPs and CNTs. For sensing applications, functionalization of CNTs sidewalls can improve the excellent potential of carbon nanotubes as sensitive material for detecting very low levels of chemical or biological molecules, enhancing the interaction between a specific chemical species and the nanotubes, as well as the selectivity of the adsorption process [21][22][23].…”

Fabrication And Properties Of Silver Based Multiwall Carbon Nanotube Composite Prepared By Spark Plasma Sintering Method

“…There are publications, which describe procedures for modification of carbon nanotubes in order to obtain required powder mixtures. Some of the methods mention the decorating of nanotubes with such metals as: Ni, Pd, Au, Ag [4,5,6]. Silver is of particular importance because of its high electrical and thermal conductivity when compared to the other metals.…”