Preparation of graphene-coated high entropy alloy nanoparticles by double pulse carbothermal shock

Abstract

High entropy alloy (HEA) nanoparticles have wide application prospects in electrocatalysis due to their unique structure. However, the surface of HEA nanoparticles has strong chemical activity due to numerous suspended and unsaturated bonds, which poses serious challenges to storage and transportation. To solve this problem, we used a double pulse carbothermal shock process to coat the surface of HEA nanoparticles with graphene. The formation mechanism of HEA nanoparticles and the graphene coating mechanism were discussed. The results showed that the HEA thin films were curled into nanoparticles by the change of orientation of twin structure under the thermal stress of carbothermal shock. After the complete HEA nanoparticles were formed, the carbon dissolved in the HEA nanoparticles will gradually precipitate out during a second carbothermal shock and form multiple layers of graphene on the surface, and forming a structure of graphene-coated HEA nanoparticles.