多孔纳米CoFe_2O_4的制备及其对高氯酸铵的热分解催化性能

采用胶晶模板法制备出具有三维多孔结构的纳米CoFe_2O_4。利用X射线衍射仪(XRD)、傅里叶变换红外(FT-IR)光谱仪、扫描电镜(SEM)、透射电镜(TEM)和N_2吸附-脱附对样品的晶型和形貌结构等进行表征,采用差示扫描量热法(DSC)对比研究多孔纳米CoFe_2O_4和球形纳米CoFe_2O_4对高氯酸铵(AP)的热分解性能的影响,并考察这两种催化剂对AP催化热分解的动力学参数。结果显示,制备出的多孔纳米CoFe_2O_4样品具有典型的尖晶石结构,孔径约200 nm;比表面积明显高于40 nm球形CoFe_2O_4,达到55.646 m~2?g~(-1)。DSC测试结果表明:多孔纳米CoFe_2O_4的加入促进了AP的热分解,最高使AP的高温分解峰温降低91.46°C,能量释放最高达1120.88 J?g~(-1),是纯AP分解放热量的2.3倍;多孔纳米CoFe_2O_4具有较高的比表面积,能提高催化反应的接触面积,使AP的高温分解峰温度更低,反应活化能较小,从而表现出比球形纳米CoFe_2O_4更高的催化活性。此外,对多孔纳米CoFe_2O_4催化AP的热分解机理进行初步探索,纳米多孔催化剂对气态中间产物的作用促进了AP的热分解。

Preparation of Nanoporous CoFe2O4 and Its Catalytic Performance during the Thermal Decomposition of Ammonium Perchlorate

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.