Metal–organic framework-derived nanocomposite metal-oxides with enhanced catalytic performance in thermal decomposition of ammonium perchlorate

Abstract

Abstract In this work, CuO@NiO nanocomposites have been prepared using a 3D metal-organic framework, [Ni(μ3-tp) (μ2-pyz)]n as precursor, where H2tp and pyz corresponds to 1,4-benzenedicarboxylic acid and pyrazine, respectively. Calcinations of the precursor at two different temperatures (400 and 500 °C) following precipitating copper nitrate by NaOH (Cu:Ni molar ratio of 1:2) resulted in metal oxide nanocomposites with different characteristics (CuO@NiO-400 (2:1) and CuO@NiO-500 (2:1), respectively). Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) coupled with EDS mapping, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS) analyses have been used to obtain compositional and morphological features of the prepared samples. The effect of calcination temperature on textural characteristics of the nanocomposites have been examined by Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods. It was found that higher calcination temperature destroyed the porous structure of the nanoparticles due to agglomeration. Catalytic performance of the nanocomposites was investigated toward thermal decomposition of ammonium perchlorate (AP) by means of differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). The results showed that the composite metal oxides (CuO@NiO) had more catalytic activity compared with CuO and NiO nanoparticles. CuO@NiO-400 (1:2) nanocomposites with larger surface area and smaller particle size exhibited significant catalytic activity compared with CuO@NiO-500 (1:2). The decomposition temperature was notably decreased from 420 to 310 °C. The released heat from AP decomposition was increased from 450 J g−1 to 1535 J g−1 over CuO@NiO-400 (1:2) nanocomposites. Also, the effect of different molar ratios (1:1 and 2:1) of CuO and NiO was investigated on AP thermal decomposition. The obtained nanocomposites are promising enough for further catalytic studies on the thermal decomposition of AP.