Patent ID: 8030242

Claim:
A process for preparing anisotropic metallic nanoparticles comprising using two different reducing agents R1 and R2 on a source of at least one metal selected from columns 8, 9 or 10 of the periodic table of the elements, reducing agent R1 having higher reducing power than reducing agent R2, said process comprising: a) one of the following: a1) impregnating a support with an aqueous solution comprising a source of at least one metal selected from columns 8, 9 or 10 of the periodic table of the elements, then bringing said support into contact with a reducing agent R1; or a2) bringing an aqueous solution comprising a source of at least one metal selected from columns 8, 9 or 10 into contact with a reducing agent R1; b) forming anisotropic metallic nanoparticles by bringing the solution or support obtained in a) into contact with reducing agent R2, which is different from R1; and c) if a) is a2), then optionally depositing the anisotropic metallic nanoparticles onto a support, wherein b) is carried out after a), in a “two-step” process by introducing the reducing agent R2 after forming seeds of metallic nanoparticles.