Hollow metal nano particles

Hollow metal nano particles comprising:

• a hollow core portion;
• and
• a shell portion consisting of a first metal and a second metal,
• wherein at least two major peaks showing an atomic percentage of at least one of the first metal and the second metal are present in element analysis data of the particles, and
• wherein the hollow metal nano particles have an average particle diameter of 12 nm or less,
• wherein the first metal is platinum (Pt), the second metal is nickel (Ni), cobalt (Co) or iron (Fe), and
• the hollow metal nano particles comprise an anionic surfactant or a cationic surfactant inside the hollow core,
• wherein the hollow metal nano particles are fabricated by a method comprising:
• 1) adding a first metal salt, a second metal salt, and a surfactant to a solvent to form a solution;
• and
• 2) adding a reducing agent to the solution formed in 1) to form the hollow metal nano particles,
• wherein the solution of step 1) is formed by forming a micelle by the surfactant and surrounding an outer portion of the micelle with the first metal salt and the second metal salt, and the hollow metal nano particles of step 2) are formed by forming the micelle region to a hollow form, and
• wherein the concentration of surfactant in the solution may be one time or more and 5 times or less of the critical micelle concentration (CMC) to water.