Tuning the Reactivity of Al/NiO@C Nanoenergetic Materials through Building an Interfacial Carbon Barrier Layer

Inspired by the crucial role of the interface layer in tuning the reactivity of nanoenergetic materials (nEMs), in this study, we report a new method to tune the energetic performances of Al/NiO@C nEMs by designing the interfacial barrier layer between the fuel and oxidizer. The carbon shell in special core-shell NiO@C nanorods derived from nickel-based metal-organic frameworks functions as a homogeneous interfacial diffusion-resistant layer between Al and NiO nanoparticles. Under the guidance of experimental time-resolved oxidation curves and theoretical simulation results, the carbon content can be easily controlled, thereby achieving the goal of tuning energetic performances. It is found that the chemical nature of the carbon barrier layer rather than its content provides the resistance against interdiffusion of Al and O atoms in the solid-state reaction, thus leading to a higher reaction onset temperature. The importance of the interfacial layer on the thermal properties of nEMs is also emphasized when compared with physically mixed ones. Combustion tests reveal that both interfacial resistance and gas generation play roles in tuning the combustion propagation, flame temperature, ignition delay time, and pressurization rate. These results indicate the promising potential of pre-engineered interfacial structure for targeted reactivity of carbon-based nEMs.