Chemistry through the lens

Scanning electron microscopy image of a Co₃O₄-Fe₂O₃ composite produced after firing a single-phase (Co,Fe)₂O₃ precursor in flowing hydrogen. Reticular porosity is a consequence of the oxygen loss associated with reducing Co³⁺ to Co²⁺. This and other routes to spontaneously form porous and composite materials are discussed in a recent feature article by Serena Corr et al.  in the Journal of Materials Chemistry (J. Mater. Chem., 2010, 20, 1413).