Synthesis of multi-walled carbon nanotube/silver nanocomposite powders by chemical reduction in aqueous solution

Abstract

Carbon nanotube (CNT)/silver nanocomposite powders with different volume fractions of CNTs 2.5, 5 and 10 vol.% were prepared by chemical reduction in solution. Multi-walled CNTs underwent surface modifications for functionalisations by acid treatments. The acid-treated CNTs were investigated by FT-IR and X-ray photoelectron spectroscopy. The spectroscopic investigations of the acid-functionalised CNTs detected that several kinds of functional groups attached with the graphene structure as well as produced short and de-caped CNTs. Acidic stannous chloride solution was used to sensitise the surface of the functionalised CNTs. Silver was deposited on the surface of sensitised CNTs with chemical reduction reaction of alkaline silver nitrate solution by formaldehyde at room temperature and pH ∼ 9. The morphology of the produced CNT/silver nanocomposite powder was investigated by high-resolution SEM and TEM. It was observed that the produced CNT/silver nanocomposite powders have decorated type of spherical silver particle size 2–5 nm deposited on the surface of CNTs as well as the CNTs were implanted in large spherical silver nanoparticles of particle size ∼200 nm. The chemical analysis of the produced powder indicates that some oxygen content is included in the prepared powders which can be reduced by heat treatment at temperatures between 300°C and 400°C under hydrogen atmosphere.