Magnetically moveable bimetallic (nickel/silver) nanoparticle/carbon nanotube composites for methanol oxidation

Multi-walled carbon nanotubes (CNTs) functionalized both by nickel and silver nanoparticles were obtained using a single step chemical deposition method in an ultrasonic bath. The new composite material was characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and cyclic voltammetry ( CV). The electroactivity of the bi-functionalized CNTs multi-walled carbon nanotubes was assessed in respect to the electrooxidation of methanol. It was found that the carbon nanotube supported silver nanoparticles have significantly higher catalytic properties than the bulk metal of the same surface area. Furthermore, it was shown that the presence of only a very small proportion of magnetic nickel nanoparticles (1.5% of the total number of metallic nanoparticles) allows the bi-functionalized carbon nanotubes to be moved magnetically in solution, making them easily recoverable after use whilst keeping an optimal electrocatalytic surface area.