After Pt cores are formed, they become catalysts with surfaces to facilitate the reduction of Ni2+ by DEG [56]. The reduction reaction is further enhanced as Pt absorbs microwaves by forming eddy currents [57] and [58], thereby achieving a temperature above the DEG solution [59]. Under such conditions, both Pt and Ni are added as nanoparticles grow in size although Pt is still favoured over Ni. Once Pt2+ is depleted, only Ni is coated on the outside of the nanoparticles.