Magnetic – Field Assisted Synthesis of Cobalt Nanowire Aerogels for Tunable Structural, Magnetic, and Electrochemical Properties

Cobalt and cobalt oxide aerogels present materials solutions to challenges in energy, sensing, and catalysis via their high porosities and surface areas, low densities, and their magnetic and electrochemical properties. Traditional synthesis methods suffer limitations including aggregation, a need for templates, and slow reactant diffusion times. We present a magnetic-field assisted synthesis to prepare cobalt nanowire (CoNW) aerogels which allows rapid CoNW growth, is scalable, and does not require templates. A variable magnetic field allowed tuning of the CoNW structural properties with higher applied fields favoring longer CoNWs and higher aspect ratios. Thermal annealing allowed conversion of the CoNWs to Co3O4. The applied field strength and annealing parameters also influenced the surface areas, pore volumes, magnetizations, coercivities, and specific capacitances. This work demonstrates the magnetic-field assisted synthesis as a fast and scalable strategy to produce CoNW aerogels with tunable nanostructure, material phase, magneto-responsiveness, and accessible surface area for electrocatalytic applications.