Two facile routes for functionalization of WS2 nanotubes with silver nanoparticles

Abstract

Silver-coated WS 2 nanotubes (NT-WS 2 ) were successfully synthesized via two wet chemistry techniques. The first employs spontaneous silver nanoparticle growth resulting from an interaction of disulfide nanotubes with AgNO 3 in aqueous suspensions at 100• C without any additional reducing agents or stabilizers. The second utilizes [Ag(NH 3 ) 2 ]OH complex to produce silver nanoparticles upon thermal decomposition. Both techniques are capable of producing Ag-NT-WS 2 nanocomposites containing 5-60 nm silver nanoparticles tightly attached to the nanotubes' surfaces. The hexagonal arrangement of sulfur atoms of the outer WS 2 layer was postulated to facilitate crystallization of silver nanocrystals with hexagonal crystallographic system (4H-Ag). The physical-chemical model for spontaneous AgNP formation is proposed.

The microstructure effect on the Au/TiO2 and Ag/TiO2 nanocomposites photocatalytic activity

“…Wet chemistry techniques are widely used for silver and gold NPs decorization of titania [8,27,35,41] and other semiconductors [61]. Among these techniques, the most popular are impregnation of semiconductor powder by previously synthesized metal NP sols and in situ growth of NPs on the semiconductors surface.…”

Gold Decoration and Photoresistive Response to Nitrogen Dioxide of WS2 Nanotubes

“…Additionally, decoration with Ag nanowires significantly improved response and recovery of NO 2 sensors based on WS 2 nanosheets . Several nanocomposites based on NT‐WS 2 and noble metals, including gold and silver plasmonic nanoparticles, were reported, however their gas sensing properties have never been studied. Important information about surface features of NT‐WS 2 ‐based nanocomposites is rather limited, while it is the key issue in understanding the sensing mechanisms of such materials.…”

WS2 nanotubes dressed in gold and silver: Synthesis, optoelectronic properties, and NO2 sensing

“…Contrary to CNT, easily enriched with surface functional groups by acidic etching [6], the outer surface of NT-WS2 is represented by a layer of sulfur atoms, which are hardly transformed to any moieties available for facile functionalization [7]. However, this sulfur atomic layer was found to be extremely beneficial for a particular case of gold/silver deposition due to the formation of strong Au-S and Ag-S bonds conditioning strong fixation of the metal nanoparticles [8,9].…”

“…Similar reduction of HAuCl4 to tiny gold nanoparticles by exfoliated MoS2 and WS2 nanosheets at room temperature was reported by Kim et al [11], however only large (hundred nanometers) irregularly shaped gold particles were formed onto NT-WS2 [8], highlighting the role of the elevated temperature in surface modification of less reactive tubular disulfide nanostructures. Noteworthy, we developed two similar techniques for decoration of NT-WS2 with silver nanoparticles employing AgNO3 and [Ag(NH3)2]OH solutions [9]. Some of the grown Ag nanocrystals had an unusual hexagonal structure (4H-Ag) due to the template effect of sulfur atoms arranged on the NT-WS2 surface.…”