Role of oxygen plasma for improved preparation of Cu/CNT Nanohybrids by RF sputtering

Abstract

Carbon nanotubes (CNTs) decorated with nanoparticles (NPs) have unique properties as catalyst carriers in sustainable energy technologies. This study mainly focuses on the optimal dry-preparation of nanohybrids made of copper (Cu)-coated CNTs through a clean magnetron sputtering technique. A distinct approach of oxygen (O₂) plasma surface functionalization is combined with the in-situ state of the deposition stage, either in static or in piezo-vibrating mode. The corresponding impact that controls the uniform deposition, chemical composition, and material loading was investigated. Dynamic light scattering (DLS) and Thermogravimetric analysis (TGA) were used to identify the best preparation conditions that impart the maximum surface modifications for improved hydrophilicity and material loading. The vibrating mode of the deposition stage continuously tumbles the CNTs during the sputtering and achieves all-around deposition. O₂ plasma has played a crucial role in grafting the surface functional groups acting as nucleation centers and attracting the sputtered Cu species with stronger interaction. The findings emphasize the advantages of O₂ plasma, particularly combined with vibrating mode for tailoring the surface properties and Cu loading at 1D nanoscale. These results demonstrated the versatility of the dry-synthesis technique, allowing the controlled preparation of high-purity nanohybrid powders with a scale-up potential.