Porous Cr₂O₃ bead with a 3D continuous pore architecture: Synthesis and its catalytic performance for decomposition of ammonium perchlorate

A mesoporous/macroporous Cr₂O₃ bead with the size of 0.2-0.3 mm and a 3D continuous pore structure (Cr₂O₃-MPB) was synthesized using an anion exchange resin as a hard template for the first time. Its structural characteristics were tested by scanning electron microscopy, X-ray diffraction, nitrogen adsorption-desorption and transmission electron microscopy, and the results showed that the 3D continuous pores of Cr₂O₃-MPB are mesoporous and macroporous with size mainly distributed in the range of 20-90 nm. The obtained Cr₂O₃-MPB was then used to catalyze the thermal decomposition of ammonium perchlorate (AP) and proved to reduce the AP thermal decomposition temperature in HTD from 411.8 °C to 337.8 °C and increase the exotherm from 450.3 J g^-1 to 1203.5 J g^-1. Notably, the advantage of the bead sample was confirmed by comparison with the commercial Cr₂O₃, illustrating that the 3D continuous pore structure of Cr₂O₃-MPB plays a vital role in promoting the AP thermal decomposition by enhanced mass transfer in it. Such a bead might show potential as an efficient combustion catalyst in solid rocket propellants.