Abstract:

Three-dimensional, nanoporous CoFe₂O₄ catalysts were synthesized, employing a colloidal crystal template method. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N₂ adsorption-desorption were subsequently used to characterize the crystal structures and morphologies of the samples. The catalytic activities of nanoporous CoFe₂O₄ and CoFe₂O₄ nanospheres during the thermal decomposition of ammonium perchlorate (AP) were also investigated by differential scanning calorimetry (DSC). The results show that the spinel framework of these materials has an ordered open network of pores averaging 200 nm in diameter. The specific surface area of the nanoporous CoFe₂O₄ was 55.646 m²·g^-1, a value that was higher than that of the nanosphere material. DSC analysis indicates that the catalytic activity of the nanoporous CoFe₂O₄ is superior to that of the spherical material during the thermal decomposition of AP, and that the nanoporous catalyst makes the peak temperature of high temperature decomposition decrease by 91.46℃. The heat release from the AP in the presence of nanoporous CoFe₂O₄ (1120.88 J·g^-1) is 2.3 times that obtained frompureAP. Both the higher specific surface area and greater quantity of active reduction sites on the nanoporous CoFe₂O₄ relative to the nanosphere material act to reduce the activation energy during the AP decomposition process. Based on the results of this work, a possible catalytic mechanismfor the thermal decomposition of AP over nanoporous CoFe₂O₄ is proposed, in which gaseous intermediates play an important role.

Key words: Colloidal crystal template, Nanoporous CoFe₂O₄, Ammonium perchlorate, Thermal decomposition, Catalysis