Three-dimensional nanostructured porous Co3O4 was synthesized on a silicon substrate via a hydrothermal route in conjunction with annealing treatment. The structure and morphology of the obtained Co3O4 samples were systemically examined using field-emission scanning electron microscopy and X-ray diffraction. The Co3O4 structures were composed of nanosheets forming a pore-network architecture that promoted Al penetration into its inner regions during deposition resulting in enhanced interfacial contact area, which significantly improve metastable intermolecular composites (MICs) burning rate and the release of energy. The successfully Co3O4 was used to synthesize Al/Co3O4 based MICs by integration with nano-Al deposited via thermal evaporation. The heat of reaction of Al/Co3O4, particularly the exothermic reaction before Al melting, was greatly enhanced by the Co3O4 nanostructures. The Al/Co3O4 based MICs were fabricated on a silicon substrate, which is very convenient for integrating MICs with silicon-based microelectromechanical systems to achieve functional nanoenergetics-on-a-chip.