Formation of carbon nanoparticles with perfectly spherical.shape and diamond structure (diamond nanospherulite) by laser-ablating a variety of carbon samples in water is reported for the first time The studies reveal ...Formation of carbon nanoparticles with perfectly spherical.shape and diamond structure (diamond nanospherulite) by laser-ablating a variety of carbon samples in water is reported for the first time The studies reveal that molten carbon nanoparticles generated by laser ablation are quenched directly by water and end up as diamond nanospherulites,possibly due to the high pressure arising from surface tension and the high stability resulting from termination of dangling bonds with hydrogen atoms.展开更多
Carbon nanoparticle appearing in perfect spherical shape, with sizes varying from tens nanometers to several micrometers, can be produced by pulsed-laser ablating different elementary carbon samples immersed in water....Carbon nanoparticle appearing in perfect spherical shape, with sizes varying from tens nanometers to several micrometers, can be produced by pulsed-laser ablating different elementary carbon samples immersed in water. A variety of samples including HOPG,graphite, arcdischarging deposite, glassy-carbon and imitation-diamond have been tried.The yield of the diamand nanospherulite is found to depend on the structure of the sample.The SAED pattern of the carbon-sphere produced from arc-discharging deposite can be at-tributed to the hexagonal structure of diamond, and its HREM image exihibits 0.38nm×0.31 nm lattice, which is just three times of the distances for (110) (d=0.126 nm) and (004) (d=0.1030nm) crystal layers of hexagonal diamond, respectively. While the SAED pattern from glassy-carbon sample displays a cubic-diamond structure. Furthermore, Raman spectra and 13C NMR indicate tetrahedral network of the spheres.展开更多
基金Project supported by the National Natural Science Foundation of Chinathe State Education Commission of China
文摘Formation of carbon nanoparticles with perfectly spherical.shape and diamond structure (diamond nanospherulite) by laser-ablating a variety of carbon samples in water is reported for the first time The studies reveal that molten carbon nanoparticles generated by laser ablation are quenched directly by water and end up as diamond nanospherulites,possibly due to the high pressure arising from surface tension and the high stability resulting from termination of dangling bonds with hydrogen atoms.
文摘Carbon nanoparticle appearing in perfect spherical shape, with sizes varying from tens nanometers to several micrometers, can be produced by pulsed-laser ablating different elementary carbon samples immersed in water. A variety of samples including HOPG,graphite, arcdischarging deposite, glassy-carbon and imitation-diamond have been tried.The yield of the diamand nanospherulite is found to depend on the structure of the sample.The SAED pattern of the carbon-sphere produced from arc-discharging deposite can be at-tributed to the hexagonal structure of diamond, and its HREM image exihibits 0.38nm×0.31 nm lattice, which is just three times of the distances for (110) (d=0.126 nm) and (004) (d=0.1030nm) crystal layers of hexagonal diamond, respectively. While the SAED pattern from glassy-carbon sample displays a cubic-diamond structure. Furthermore, Raman spectra and 13C NMR indicate tetrahedral network of the spheres.
