Synthesis, growth mechanism and thermal stability of copper nanoparticles encapsulated by multi-layer graphene

• Published in: Carbon (New York) Vol. 50; no. 6; pp. 2119 - 2125
• Main Authors: Wang, Shiliang, Huang, Xiaolin, He, Yuehui, Huang, Han, Wu, Yueqin, Hou, Lizhen, Liu, Xinli, Yang, Taimin, Zou, Jin, Huang, Baiyun
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.05.2012; Elsevier
• Subjects: Carbon; CHEMICAL VAPOR DEPOSITION; Chemistry; Colloidal state and disperse state; Copper; Cross-disciplinary physics: materials science; rheology; ENCAPSULATION; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; General and physical chemistry; Graphene; Materials science; Multilayers; Nanoparticles; PARTICLES; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Physics; Shells; Specific materials; THERMAL STABILITY; THERMOGRAVIMETRIC ANALYSIS; Copper II; Iron; Cobalt; Precursor; Thermal stability; Nanoparticles; Precipitation; Synthesis; Oxidation; Copper; Differential scanning calorimetry; Powders; Atmospheres; Thermogravimetry; Air; Dissolution; High-resolution methods; CVD; Thickness; Monocrystals; Transmission electron microscopy; Transition elements; Growth mechanism; Nickel; Coalescence
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2011.12.063

Copper nanoparticles encapsulated by multi-layer graphene have been produced in large quantity (in grams) by metal-organic chemical vapor deposition at 600°C with copper(II) acetylacetonate powders as precursor. The obtained graphene/copper shell/core nanoparticles were found to be formed by a novel coalescence mechanism that is quite different from the well-known dissolution–precipitation mechanism for some other graphene/metal (such as nickel, iron or cobalt) shell/core nanoparticles. Differential scanning calorimetry and thermogravimetric analyses showed that the copper nanoparticles encapsulated by multi-layer graphene with a thickness of 1–2nm were thermally stable up to 165°C in air atmosphere. Moreover, high-resolution transmission electron microscopy showed that the single-crystal copper nanoparticles, after exposure to air for 60days, did not exhibit any sign of oxidation.