Ambient spark generation to synthesize carbon-encapsulated metal nanoparticles in continuous aerosol manner

Abstract

We report the use of spark generation in an inert gas atmosphere to synthesize carbon-encapsulated metal nanoparticles (CEMNs) in a continuous aerosol manner using a metal (nickel, cobalt, iron)-graphite carbon electrode configuration without the use of a vacuum. The spark-generated particles consisted of CEMNs and carbonaceous aggregated debris. The outer layer of the CEMNs showed parallel fringes (ordered graphitic nanostructures) while the debris consisted of disordered nanostructures. Electron and X-ray diffraction showed that both metal and graphite in the CEMNs were the pure elements except for iron-carbon, which contained a carbide phase. Based on the order of the activation energies for carbon diffusion into a metal: iron-carbon (10.5-16.5 kcal mol(-1)) < cobalt-carbon (34.7 kcal mol(-1)) approximately nickel-carbon (33.0-34.8 kcal mol(-1)), it was concluded that carbide particles form more easily from elemental iron than nickel or cobalt. The metal-to-carbon mass fractions of the spark-generated particles from nickel (anode)-carbon (cathode), cobalt-carbon, and iron-carbon spark configurations were 18.7, 28.3, and 11.2%, respectively, while the mass fractions for the configurations of metal (cathode)-carbon (anode) were 6.4, 9.1, and 4.3%, respectively. Similarly, the yield of CEMNs from the metal (anode)-carbon (cathode) electrodes was higher (54, 61, and 53%) than that of metal (cathode)-carbon (anode) electrodes (18, 30, and 18%).

Magnetic properties of carbon coated Fe, Co and Ni nanoparticles

“…The interlayer distance of the encapsulation is 0.34 nm corresponding to graphite (0 0 2) planes. The inter-lattice distance of the core is 0.20 nm [29], which is in good agreement with that of fcc-Ni (1 1 1) planes.…”

A Coconut Leaf Sheath Derived Graphitized N‐Doped Carbon Network for High‐Performance Supercapacitors

“…We calculated the d spacing from the image using Image‐j software and it was found to be 0.347 nm. This is in almost in par with our XRD findings, where d spacing for a [0 0 2] plane is 0.336 nm for graphite (JCPDS‐75‐1621) . This reiterates that we have a highly graphitized sample.…”

Green manufacturing of metallic nanoparticles: a facile and universal approach to scaling up

“…[18][19][20][21][22] Among the numerous gas phase methods, rapidly quenched gas-phase spark ablation operated at ambient pressure provides great versatility in the synthesis of inorganic NPs consisting of a wide variety of conducting or semiconducting materials including rare earths (that are difficult to produce with traditional wet-chemistry methods), thermodynamically metastable materials, 23 and alloys (e.g., steel) with virtually unlimited mixing possibilities. 7,19,[24][25][26][27] In addition, the method offers good control over particle size which can range from that of atomic clusters to that of singlets or agglomerates consisting of sub-10 nm primary particles. 25,28,29 This technique have focused on fabricating NPs using spark ablation (at low frequencies) for a number of new applications (Table S1).…”