Synthesis and Modification of Metal Nanoparticles by Plasma over an Aqueous Solution under Pressurized Argon

Metal−based nanoparticles have been used in diverse industrial applications owing to their physicochemical properties. Here, the electric field produced by pulsed high−voltage discharge plasma over an aqueous solution surface that was generated under high−pressure argon environment would be employed to synthesis and to modify metal materials. The plasma reactor was made of stainless steel and contained two sapphire windows to monitor the plasma performance. The experiments were conducted at room temperature (25 − 28 °C) with argon environment at a pressure of 3.0 MPa and the DC power supply at 18.6 kV was introduced into the reactor through the electrode to generate pulse electrical discharge plasma. The metal rod electrode which was used as a material source for nanoparticles generation was placed over an aqueous solution containing glycine, as carbon source, to introduce electrical discharge plasma. The scanning transmission electron microscopy which was equipped with energy dispersion spectroscopy (STEM coupled with EDS) indicated that titanium dioxide and iron oxide with and without carbon covered were successfully produced in nano−scale (<100 nm).