Chemical synthesis of periodic macroporous NiO and metallic Ni

A general procedure for synthesizing macroporous metals with 250-500 nm monodisperse voids surrounded by nanocrystalline metal walls is reported. The method is based on templated precipitation and subsequent chemical conversion of the precursors to a macroporous metal or metal oxide. The metal oxide can be further converted to a purely metallic, ordered macroporous solid by complete reduction in H or to a metal-oxide/metal composite by partial reduction. The synthesis rely on filling the void spaces between close-packed spheres with liquid metal alkoxides, resins or gas phase precursors. As a result, improved performance may be possible in applications such as porous electrodes or supports for solid electrolytes.