Preparation of TiO 2 /CNTs nanocomposite and its catalytic performance on the thermal decomposition of ammonium perchlor
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Preparation of TiO2/CNTs nanocomposite and its catalytic performance on the thermal decomposition of ammonium perchlorate Sheng‑Hao Meng1,2 · Ji‑Fang Liu1 · Xiang‑Tong Kong1 · Shi‑Guo Du2 Received: 12 March 2020 / Accepted: 3 June 2020 © Springer Nature Switzerland AG 2020
Abstract 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 T iO2 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 T iO2/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 T iO2 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. Keywords Carbon nanotube · Nanocomposite · Ammonium perchlorate · Catalyze
Introduction Ammonium perchlorate (AP) is the most commonly used oxidant in composite solid propellants; its thermal decomposition performance has a great influence on the burning behavior of propellants. Over the past dozens of years, the thermal decomposition characteristics of AP are extensively investigated and summarized in many reviews [1, 2]. Transition metal oxides (TMOs) are often adopted as solid propellants burning rate modifiers, by means of improving the thermal decomposition of AP. The catalytic effect of TMOs on the thermal decomposition reactions may be attributed to the semiconductor properties (degree of p or n nature), charge transfer process, electron transfer process, etc. The p-type semiconductive nature of oxides is reportedly contributory in enhancing the reactivity [3, 4]. Among the
* Sheng‑Hao Meng [email protected] 1
High-tech Institute, Fan Gong‑ting South Street on the 12th, Qingzhou, Shandong, China
Mechanical Engineering College, Shijiazhuang, Hebei, China
2
various TMOs, TiO2 is an abundant, low cost, and nontoxic material and thus has been extensively studied for various applications such as pigments, cosmetics, photocatalysts, solar cells and water treatment, as well as the decomposition of AP [5–7]. In general, the performance of the catalytic materials is closely related to the specific surface area of the active components. To achieve a high performance, active components hav
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