Layered Double Hydroxide-Mediated Heterogeneous Growth of Metal-Organic Frameworks on Nanoaluminum for Highly...

Nanothermites offer the dual advantages of high energy density and exceptional reactivity, making them highly promising for advanced energetic applications such as aerospace and microelectromechanical systems (MEMS). However, their mass transfer efficiency is hindered by nanoparticle agglomeration. Achieving structurally modified nanothermites with large, controllable interfacial contact without sacrificing energy release is challenging. To address this issue, we propose a strategy to mediate the heterogeneous growth of metal-organic frameworks (MOFs) on nanoaluminum (nano-Al) using layered double hydroxides (LDHs). The resulting Al@porous metal oxide (Al@pMO) from Al@MOF maximizes interfacial contact without introducing interlayers. The composition of Al@pCuO derived from Al@HKUST-1 is precisely adjusted by varying the feed rate of HKUST-1. Uniform growth of HKUST-1 thin films on nano-Al at high feed rates results in a sub-10 nm layer thickness in 10% Al@HKUST-1. Lower feed rates promote MOF growth to encapsulate nano-Al. Al@pCuO with 33 wt % CuO demonstrates a 3-fold enhancement in energy release in argon compared to Al/CuO mixtures, achieving 78% of the theoretical heat release. The growth mechanisms of LDH and MOF are further discussed. Notably, 10% Al@pCuO with an extreme equivalent ratio (Φ = 48.9) is successfully ignited, indicating more efficient mass transfer. The larger flame areas and higher dynamic pressures of Al@pCuO compared to Al/CuO mixtures highlight its enhanced energetic performance. This strategy provides a solution to the dilemma of interfacial contact and energy release. Al@pCuO with highly efficient energy release and precisely adjustable compositions shows excellent potential for MEMS and aerospace applications.