Observation on the thermal stability of multi-layer graphene with metal nanoparticles with 0D structure

Abstract

We studied the effect of rapid thermal treatment on multi-layer graphene with metal particles in an oxygen gas atmosphere. The multi-layer graphene-coated copper nanoparticles (MGCNs) were produced via electrical explosion in an isopropyl alcohol liquid medium. The MGCNs usually consist of multi-layer graphene shells that tightly surround the core copper nanoparticles without obvious voids. A fracture is induced by tearing the multi-layer graphene structure and the oxidized copper metal particles of the MGCNs after thermal treatment in oxygen gas at a low temperatures, including 25, 100, 200, and 300 °C. The MGCNs were characterized via Raman spectroscopy to obtain the graphene peak and its variation according to the oxygen gas temperature. Transmission electron microscopy was conducted to confirm the effect of the oxygen on the multi-layer graphene and copper nanoparticles phase using oxygen gas. The structure of the copper nanoparticles was observed via x-ray diffraction, and x-ray photoelectron spectroscopy was used to measure the chemical bonding on the multi-layer graphene surfaces treated with oxygen gas. We can show systematically optical images of changes in multi-layer graphene morphology like the 0D structure and existence of functional groups through various analyses after rapid thermal treatment in oxygen.