Preparation of Copper Nanoparticles Using Dielectric Barrier Discharge at Atmospheric Pressure and its Mechanism

Abstract

Dielectric barrier discharge (DBD) cold plasma at atmospheric pressure was used for preparation of copper nanoparticles by reduction of copper oxide (CuO). Power X-ray diffraction (XRD) was used to characterize the structure of the copper oxide samples treated by DBD plasma. Influences of H2 content and the treating time on the reduction of copper oxide by DBD plasma were investigated. The results show that the reduction ratio of copper oxide was increased initially and then decreased with increasing H2 content, and the highest reduction ratio was achieved at 20% H2 content. Moreover, the copper oxide samples were gradually reduced by DBD plasma into copper nanoparticles with the increase in treating time. However, the average reduction rate was decreased as a result of the diffusion of the active hydrogen species. Optical emission spectra (OES) were observed during the reduction of the copper oxide samples by DBD plasma, and the reduction mechanism was explored accordingly. Instead of high-energy electrons, atomic hydrogen (H) radicals, and the heating effect, excited-state hydrogen molecules are suspected to be one kind of important reducing agents. Atmospheric-pressure DBD cold plasma is proved to be an efficient method for preparing copper nanoparticles.

Dielectric Barrier Discharge Plasma Deoxidation of Copper Surfaces in an Ar/SiH4 Atmosphere

“…Among different techniques, non-thermal plasma reduction of copper oxides demonstrates promising results [4][5][6][7][8][9]. As it was shown in our previous research [9], few nanometer-thick native oxide layers were almost completely removed from copper surfaces within 20 s of treatment using a dielectric barrier discharge (DBD) plasma in an Ar/H 2 gas at 100 hPa.…”

A review on the recent progress, challenges, and perspectives of atmospheric‐pressure cold plasma for preparation of supported metal catalysts

“…Therefore, it is technically feasible to keep the gas temperature of AP cold plasma at low temperatures. For example, the gas temperature for plate‐to‐plate DBD cold plasma is about 200 °C after 15 min stabilizing time . In addition, to limit the gas temperature, the treatment for plate‐to‐plate DBD cold plasma was generally not continuously operated.…”

“…The results showed that no copper NPs can be detected without adding H 2 gas into the cold plasma, and the highest reduction rate of copper oxide was achieved at 20%H 2 content. The optical emission spectra indicated that copper oxide was not reduced by excited‐state hydrogen atoms or heating effect, and excited‐state hydrogen molecules and hydrogen radicals were proposed to be the reducing agents . Hydrogen radicals were also deemed to be the reducing agents when using sonochemical deposition method and hot‐wire method for metal ions reduction.…”

Surfactant-free synthesis of copper nanoparticles and gas phase integration in CNT-composite materials

“…Xu Zhijian et al have investigated the use of dielectric barrier discharges fed with hydrogen (H 2 ) to reduce copper oxide and obtain Cu-NPs (~35 nm in diameter). 21 Masaaki Nagatsu et al investigated an Ar/H 2 radio-frequency (RF) microplasma with a copper wire sacrificial electrode (1 mm diameter) showing the possibility of producing nanostructured copper thin films. 22 Another study by G. Dinescu et al was carried out with an argon RF microplasma jet without hydrogen, also with a sacrificial copper electrode (a copper cylinder in this case).…”