Abstract Free-standing nanoparticles are a ubiquitous requirement for high-efficiency catalytic applications. Here, we report the catalytic pyrolysis of hydroxyl terminated polybutadiene (HTPB) binder in composite propellant by free-standing CuO nanoparticles synthesized through a novel aqueous thermolysis synthetic route. The formation mechanism of CuO nanocatalyst and the reactions between precursors were followed up by analyzing the thermal events occurred and residual analysis. Composite solid propellant samples were prepared with 0.5%, 1% and 2% CuO nanocatalyst and the catalytic pyrolysis as well as burn rate studies were conducted. By the addition of 2% nanocatalyst, complete pyrolysis of the HTPB binder occurs and the burn rate increases by > 6% at ambient pressure. The catalytic effect of the CuO nanocatalyst on the high-temperature decomposition products of AP resulting in the formation of reactive intermediates and subsequent synergistic effect leads to the complete pyrolysis of the binder leading to the increase in the propellant burn rate.