Synthesis of CdO nanostructures by nano-second pulsed discharges in liquid nitrogen

In this work, we report on the synthesis of Cd nanostructures by nano-second pulsed electrical discharges generated between two pure cadmium electrodes in liquid nitrogen. These nanostructures are oxidized in air after evaporation of the cryogenic liquid, leading to CdO. An investigation of the effect of discharge voltage on the synthesis process was conducted. Transmission Electron Microscopy analyses show that, contrary to other metallic nanoparticles synthesized by the same process, CdO nanoparticles self-assemble to give hollow micrometric cubes that transform into bunches of nanowires when the applied voltage increases. Time-resolved optical emission spectroscopy performed on the discharge during synthesis shows the presence of ionic and neutral Cd species in the discharges. A growth mechanism of Cd objects along the electric field lines in the discharge is proposed.