Hydrothermal Synthesis of Microscaled Cu@C Polyhedral Composites and Their Sensitivity to Convergent Electron Beams.

Copper microparticles (2−5 um) encapsulated in carbonaceous shell polyhedral composites were mildly prepared via a one-pot hydrothermal process using copper nitrate, glucose, and sodium citrate at 150 °C, in which the glucose was found to play reducer and graphite source roles during the formation of these core−shell-like composites. Thermal stability results indicated that their weights remain almost unchanged below 240 °C in ambient atmosphere. It is interesting that the copper microparticles could be partially released out and translated into monodisperse Cu nanoparticles around the initial composites under the convergent electron beams in a transmission electron microscope (TEM). This phenomenon is an appealing discovery, which might endow the Cu@C composite with new functions; for example, it might be applied as a sensitive detector for the leakage of electron beams or other substances for the sake of being a safeguard. In addition, the corresponding hollow carbonaceous polyhedra were also obtained after the acid treatment, which might be used as a template to fabricate other kinds of polyhedra. [ABSTRACT FROM AUTHOR]