Super-hierarchical Ni/porous-Ni/V2O5 nanocomposites

Abstract

Hierarchical nanomaterials are of great interest due to their unique surface properties such as large surface area and high reactivity. In the present research, super-hierarchical (porous-) nickel hosted vanadium oxide (Ni/porous-Ni/V₂O₅) nanocomposite was fabricated using a simple, low-cost, and environmentally-friendly method. A nickel substrate was electrodeposited with vertical pores of ∼10 μm in diameter through hydrogen bubbles as “dynamic templates”. Two-dimensional V₂O₅ nanosheets were subsequently synthesized directly on the Ni/porous-Ni substrate surface using a hydrothermal method followed by annealing. Peony-like micro-configuration of V₂O₅ was found and crystallography was confirmed using high-resolution characterization. Further analysis indicated that the interface was formed between Ni (111) and V₂O₅ (100). The small lattice mismatch of 1.2% at the interface facilitated the 2D directional growth of V₂O₅ nanosheets on the Ni surface. The specific surface area and porosity of annealed Ni/porous-Ni/V₂O₅ nanocomposite was as high as 15.3 m² g⁻¹ and 55.1%. The advantage of the structure was found in the heat dissipation. Such super-hierarchical structure is anticipated to be used in applications such as coatings to improve cooling of macro- and micro-devices.