Preparation of TiO2/CNTs nanocomposite and its catalytic performance on the thermal decomposition of ammonium perchlorate

Composite particles of carbon nanotubes (CNTs) and titanium dioxide (TiO2) were prepared by a sol-flux method. Characterization of TiO2/CNTs nanocomposite was performed by X-ray powder diffraction (XRD), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The results show that TiO2 nanocrystals (mixed anatase and rutile) are successfully deposited on the surface of CNTs, forming a granular coating with a thickness of about 2 nm. It is possible that the growth of TiO2 on the surface of CNTs is implemented by anchoring TiO2 through hydroxyl and carboxylic functional groups. In the presence of TiO2/CNTs nanocomposite, the peak temperature of the high-temperature decomposition of ammonium perchlorate (AP) decreased by 52.5 °C, better than other samples including the one of simply mixed TiO2 and CNTs. The catalytic influence is evident even with 1% catalyst concentration. The thermal kinetic constant for the catalytic decomposition of AP is computed using model free (isoconversional) Flynn–Wall–Ozawa approach. It shows that although the two exothermic decomposition peaks merged into one, the low-temperature decomposition stage still exists, and accounts for about thirty percent of the whole reaction.