The synthesis of nano-fuzz W2N layer using dense helium and nitrogen plasma

Abstract

Owing to the direct activation of reactant species, plasma has been playing a role in material synthesis and surface modification since the mid-1970s, especially for the production of nanomaterials. Tungsten nitride with nanostructures has attracted much attention for applications in catalysis and electrocatalysis, due to their noble metal-like properties. In this work, we propose a two-step strategy to prepare tungsten nitride (W2N) layer simply from tungsten sample by means of dense helium and nitrogen plasma treatment. Various surface characterization and cross-section analysis methods have confirmed the formation of W2N nano fuzz structure. After a sequential exposure to helium plasma for 20 minutes and nitrogen plasma for 30 minutes, corresponding to the ion fluence of 8.4 × 1025 m−2 and 2.3 × 1026 m−2 respectively, a nano-fuzzy layer with thickness of ~700 nm has been formed on tungsten surface and the core-shell structured W2N/W nano fibers are around 40 nm in diameter. The synthesis of nanostructured W2N via plasma environment has not only broadened the application of plasma methods, but also offers a facile and universal way for the design of materials with different morphologies and properties.