Fractal porosity in metals synthesized by a simple combustion reaction

Abstract

A simple modification of a combustion method has been used for the production of ultraporous metals in air. Nitrates of different metallic elements were reacted with glycine as a reducing fuel. The glycine to nitrate ratio can be simply used to control the formation of oxides or, in the case of fuel-rich mixtures, the formation of metals such as Ni, Co, Cu or Ag. Furthermore, the metallic monoliths obtained present a remarkable porosity of fractal nature (from macro to nano scales) with pores ranging from many microns down to at least 5 nm. This exceedingly simple approach shows the way for the design and synthesis of complex porous microstructures of metals for the wide variety of applications where interface optimization is crucial.