Carbon nanotube synthesis using refractory metal nanoparticles and manufacture of refractory metal nanoparticles

A method for manufacturing refractory metal nanoparticles, comprising:

• providing a solvent;
• providing a surfactant comprising a first surfactant configured to stabilize low oxidation states of a refractory metal and a second surfactant configured to protect refractory metal nanoparticles;
• providing a refractory metal precursor, the refractory metal precursor comprising the refractory metal and one or more additional elements;
• providing a reactant for reacting with the refractory metal precursor;
• and
• forming the refractory metal nanoparticles surrounded by the second surfactant,
• wherein the refractory metal comprises rhenium, tungsten, tantalum, or hafnium, and
• wherein if the refractory metal comprises rhenium, the refractory metal nanoparticles comprise rhenium nanoparticles, if the refractory metal comprises hafnium, the refractory metal nanoparticles comprise hafnium nanoparticles, if the refractory metal comprises tantalum, the refractory metal nanoparticles comprise tantalum nanoparticles, and if the refractory metal comprises tungsten, the refractory metal nanoparticles comprise tungsten nanoparticles.