Compositions containing a first reactant; an emulsion comprising a surfactant and silicon dioxide (SiO.sub.2) nanoparticles; and a carrier fluid containing a second reactant and methods of making. When the first and second reactants react, they generate heat. At a first time, the emulsion surrounds the first reactant, and the carrier fluid with the second reactant surrounds the emulsion. At a second time, the emulsion surrounds a first portion of the first reactant; and a second portion of the first reactant surrounds the emulsion.

Emulsion explosives with gas bubbles that are resistant to in-borehole migration or coalescence are disclosed herein. Such emulsions can be sensitized by mechanically-introducing gas bubbles into the emulsion. Resistance to gas bubble migration and coalescence can be achieved by homogenization, without the need for bubble stabilization agents.

A sensitizing composition for generating gas bubbles in an energetic hydrogen peroxide emulsion is disclosed. The sensitizing composition comprises a liquid carrier, a solid hydrogen peroxide catalyst which is dispersed in the liquid carrier and; a coating agent which is non-soluble in hydrogen peroxide and in water and which is arranged to coat the solid hydrogen peroxide catalyst dispersed in the liquid carrier. A method of preparing such a sensitizing composition is also disclosed.