Carbon nanotubes (CNTs), including single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs), are important carbon-based materials [1,2]. Since the CNTs were discovered [3,4], they have been intensively studied and have received a great deal of attention for their applications in a wide variety of areas, due to their excellent properties which involving high specific surface area, high electronic conductivity, outstanding chemical and electrochemical stability, one dimensional tubular-structure and so on [5—8]. On the other hand, owing to their unique electric, magnetic, optical, and catalytic properties, metal nanoparticles (NPs) have emerged as a new class of compounds that are interesting in several areas from chemistry to physics, to material sciences, to biology and medicine [9,10]. Importantly, these properties differ from those of the bulk materials and mainly depend on the particle size and morphology [11—13]. The hot research points in metal NPs focus on the synthesis of noble metal NPs such as Au, Ag, Pt, Pd, Ru and their alloys [14—18].
