Synthesis of CuO nanorods and their catalytic activity in the thermal decomposition of ammonium perchlorate

doi:10.1016/j.jallcom.2007.10.058

Journal of Alloys and Compounds

Volume 464, Issues 1–2, 22 September 2008, Pages 532-536

https://doi.org/10.1016/j.jallcom.2007.10.058 Get rights and content

Abstract

CuO as-prepared samples were prepared at room temperature using the mixed water–ethanol solvents. After hydrothermal treatments on these samples at high temperatures, CuO nanorods were controlled to have surface areas ranging from 72.1 to 7.2 m² g⁻¹. All CuO nanorods were characterized by X-ray diffraction (XRD), thermogravimetric (TG) analysis coupled with differential thermal analysis (DTA), transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET) technique, and Fourier transformation infrared spectroscopy (FTIR). CuO nanorods showed a surface hydration which was increased with decreasing the surface area. CuO nanorods were studied as an additive for promoting the thermal decomposition of ammonium perchlorate (AP). With the addition of CuO nanorods, thermal decomposition temperature of AP decreased. Large surface areas of CuO nanorods promoted AP decomposition, while surface hydration did not have any apparent influence. These observations were explained in terms of the surface O²⁻ species that accelerate the proton transfer in AP decomposition.

Introduction

Ammonium perchlorate (AP) is one of the main oxidizing agents that have been used in various propellants. The burning behavior of propellants is highly relevant to the thermal decomposition of AP. Thermal decomposition of AP has been extensively studied by taking advantages of the catalytic activities of many transition metal oxides [1], [2]. Among all transition metal oxides, CuO nanocrystals show particular chemical reactivity due to their high concentrations of dislocations and large surface areas [3]. It is well known that catalytic performance of nanocrystals is superior to that of bulk [4], in which preparation methods and morphologies of nanocrystals are expected to have different effects on the thermal decomposition of AP. Recently, Luo et al. [5] demonstrated that CuO nanocrystals of various shapes have prominent catalytic activities in promoting AP decomposition, while the average particle size of nanocrystals was surprisingly concluded to have no impacts on the catalytic activity of AP. As a result, the underlying mechanism of nanoparticle additives in the thermal decomposition of AP still remains unclear, most likely because of lack of systematic study about the effects of particle size (or surface area) of CuO nanocrystals on the catalytic activities. Therefore, synthesis of CuO nanocrystals with different particle sizes is fundamentally important, which allows to understand the mechanism of the thermal decompositions of AP and furthermore the burning behavior of propellants.

Many synthesis methods have been reported to prepare CuO nanocrystals with an aim to achieve tunable surface areas. Annealing, arc spray, and precipitation–pyrolysis methods are frequently used to produce CuO [6], [7]. As is well known, the samples prepared by high-temperature calcinations and pyrolysis have the drawbacks of non-uniformity [8]. Alternatively, hydrothermal and solvothermal processes are powerful to synthesize nanocrystals with homogeneous particle sizes [9], [10]. However CuO nanocrystals by solvothermal conditions are always reduced to Cu₂O or Cu by the solvents in forming unwanted impurity phases [11]. Therefore, a challenge to the optimized catalytic performance in thermal decomposition of AP is the preparation of CuO nanocrystals with controllable surface areas.

In this paper, we developed a simple combined methodology to CuO nanorods with BET surface area of 76.5 m² g⁻¹ at room temperature. With the help of subsequent hydrothermal treatments, CuO nanorods were prepared to show different surface areas. We found that the thermal decomposition behaviors of AP were significantly enhanced by increasing the surface areas of CuO nanorods.

Section snippets

Sample preparation

Chemical reagents of Cu(NO₃)₂·3H₂O (99.5%) and NaOH (96%) were used as the starting materials. At room temperature, 400 mL of 0.25 M Cu(NO₃)₂·3H₂O in ethanol was slowly added into 200 mL of 1.25 M NaOH in ethanol under stirring in a flask to form a black precipitate. Two hundred millilitres of water were then added to this mixture. After ageing at room temperature for 8 h, the precipitated product was washed fully with distilled water and dried in an oven at 100 °C for 6 h. The powder obtained was

Results and discussion

First, we briefly summarized the preparation conditions that yielded pure phase CuO nanocrystals with different particle sizes. When the samples were prepared by solvothermal process at 120 °C for 6 h in ethanol solvent, as shown in Fig. 1, the final product was a mixture of Cu₂O and CuO. Therefore, solvothermal process is not suitable for the preparation of CuO nanocrystals with controlled sizes. Instead, pure CuO samples were achieved in water–ethanol solvent at room temperature (Fig. 2). Since

Conclusions

This work explored the optimization of the thermal decomposition of AP using CuO nanorods as the additives. CuO nanorods with different surface areas were achieved by hydrothermal treatments. With increasing the surface area from 7.2 to 76.5 m² g⁻¹, AP decomposition was significantly improved. AP showed two decomposition stages at low temperatures and high temperatures. Addition of CuO nanorods in AP accelerated the high-temperature decomposition process that involves a proton transfer on

Acknowledgments

This work was financially supported by NSFC under the contract (Nos. 20773132 and 20771101), National Basic Research Program of China (973 program, No. 2007CB613306), Science and Technology Program from Fujian Province (Nos. 2005HZ01-1 and 2006L2005), Directional program (KJCX2-YW-M05) and a grant from Hundreds Youth Talents Program of CAS (Li GS).

References (21)

D.V. Survase et al.
Prog. Cryst. Growth Charact. Mater.
(2002)
W. Oelerich et al.
J. Alloy Compd.
(2001)
Y.P. Wang et al.
Thermochim. Acta
(2005)
M.J. Kao et al.
J. Alloy Compd.
(2007)
S.J. Lei et al.
Mater. Lett.
(2006)
Z.S. Hong et al.
Mater. Lett.
(2002)
N.B. Singh et al.
Thermochim. Acta
(2002)
L.J. Chen et al.
J. Therm. Anal. Calorim.
(2008)
F. Solymosi et al.
J. Catal.
(1962)
A.M. El-Awad et al.
Thermochim. Acta
(1988)

There are more references available in the full text version of this article.

Cited by (277)

Catalytic properties of 3D flower-likeMgCo<inf>2</inf>O<inf>4</inf>/MXene composites for the thermal decomposition of ammonium perchlorate by one-pot synthesis
2024, FlatChem
The catalytic active sites of the materials have a major role in the catalytic activity of nanocatalytic materials for the heat thermal decomposition of ammonium perchlorate. By adopting one-pot strategy to load MgCo₂O₄ onto MXene nanosheets, we were able to create highly dispersed MgCo₂O₄/MXene composites that improved the dispersion of the nanoparticles and increased the catalytic active sites. The MgCo₂O₄/MXene catalytic active sites were clearly optimized (Specific surface area increased from 115.4 of MgCo₂O₄ to 168.8 m²·g⁻¹), according to the BET results. The performance tests demonstrated that the MgCo₂O₄/MXene composite effectively decreased the thermal decomposition temperature of AP, and the MgCo₂O₄/MXene composite significantly reduced the peak decomposition temperature of AP by 208.3 °C (from 471.2 °C of pure AP to 262.9 °C). The decomposition heat of AP increased from 782 J·g⁻¹ of pure AP to 1453 J·g⁻¹. In addition, the apparent activation energy of AP dropped from 296.19 kJ·mol⁻¹ to 119.48 kJ·mol⁻¹. Application of MgCo₂O₄/MXene composite to AP/HTPB-based composite solid propellants (CSPs) for combustion experiments resulted in an appreciable reduction in ignition delay time of ∼ 45 ms (from ∼ 51 ms to ∼ 6 ms). The highly dispersed MgCo₂O₄/MXene composite was a positive catalyst for AP-based composite solid propellant.
One-dimensional copper oxide nanorods with potential anticancer effects against melanoma cells
2024, Arabian Journal of Chemistry
In this study, one-dimensional copper oxide nanorods (CuO NRs) as new type anticancer particles were synthesized by hydrothermal method along with sonication. Afterward, the biological properties of synthesized CuO NRs against murine B16F10 melanoma with high metastatic potential and normal fibroblast cell line (3 T3) were evaluated. XRD pattern of synthesized CuO NRs revealed a crystalline structure and FT-IR study disclosed that bands at 438–607 cm⁻¹ and 1010 cm⁻¹ are typically associated with the stretching and bending vibrations of the Cu–O bond. DLS study indicated that prepared NRs have a size distribution in the range of 37–99 nm in solution, with a zeta potential value of −37.00 mV. Finally, TEM analysis demonstrated that CuO NRs have a nanorod-like morphology with an average particle size of 5 nm in width and 25–100 nm in length. Furthermore, we discovered that CuO NRs provided an apparent and selective antiproliferative effect on B16F10 melanoma cells at a minimum concentration of 10 µg/ml, associated with induction of membrane leakage and elevation of oxidative stress. Also, induction of apoptotic process was observed in melanoma cells following exposure to CuO NRs mediated by elevation of cytochrome c, AIF, caspase-3, caspase-9, Bax, and downregulation of Bcl-2 genes and proteins. Therefore, it was deduced that both caspase-dependent and caspase-independent pathways were associated with anticancer mechanisms of CuO NRs against B16F10 melanoma. In conclusion, CuO NRs could be appointed as potential nanostructures in the modulation or prevention of skin cancer and may be an indication of a new potential anticancer compound in the treatment of melanoma, which warrants further investigations in future studies.
Physiochemical aspect of different CuO catalyst surface to APC thermochemical transformation
2024, Surfaces and Interfaces
Ammonium perchlorate (APC) as an oxidizer component of solid propellant is studied experimentally due to its complex nature of decomposition reactions concerning solid-stated theories. To reveal the surface-structure chemistry of copper oxide (CuO) as a catalyst to decomposition reactions of APC, CuO (26∼675 nm) in cubical, leaf, leaf sphere, and rod-like structures successfully prepared and crystallized with APC to distinctive CuO/APC (10–20 μm) composites. HAADF-STEM, XPS along Raman, and BET characterize copper oxide's chemically enhanced surface activity. TG-DSC-QMS detects the reaction process between CuO and APC, and a high-speed camera records the combustion process of CuO/APC in the open air. The results show that other than surface area, the surface adsorption oxygen property is the key parameter to control the catalytic effect. The CuO-nanorods provided the highest chemical species of higher Cu¹⁺/Cu²⁺ along maximal surface adsorb oxygen to chemisorption of NH₄⁺ and ClO₄⁻. The kinetic analysis found an increase in conversion rate, activation energy with a higher frequency factor, and rate constant by CuO addition to APC.
Thermal decomposition and combustion behavior of the core-shell Al@AP composite embedded with CuO as a catalyst
2024, Fuel
Conventional solid propellants suffer from undesirable combustion performance due to the poor mass and heat transfer between metal fuels and oxidizers, as well as a lack of catalytic active sites between the catalyst and catalyzed objects. Embedding metal fuels and catalysts within the oxidizer has shown promise in improving the overall combustion performance of HTPB/AP/Al and HTPB/AP/RDX/Al composite solid propellants. However, the underlying mechanisms responsible for this enhancement remain to be further understood. In this study, we investigated the reactivities of core–shell Al@AP and Al@AP/CuO composites using thermal analysis and combustion diagnostic techniques. The results demonstrated that the decomposition of AP was promoted, as evidenced by a lower peak temperature (415.2–334.7 ℃), higher total heat release (116.4–720.8 J·g⁻¹), a transition in the decomposition physical model from the random nucleation and 2D/3D growth of nuclei model to the auto-catalytic model, and increased generation of NO₂. Furthermore, the Al@AP/CuO propellant pellet exhibited a more stable flame without agglomeration, and the condensed combustion products (CCPs) contained a lower amount of unreacted Al compared to that of conventional mixtures. These findings highlighted the potential of core–shell Al@AP and Al@AP/CuO composites as replacements for discrete ingredients of solid propellants, thereby offering improved performance for next-generation propulsion systems.
Copper oxide nanoparticles (CuO-NPs): Synthesis, characterization and evaluating their ability to remove methylene blue from aqueous solutions without UV irradiation and in the absence of H<inf>2</inf>O<inf>2</inf>
2024, Ceramics International
In this work, CuO nanoparticles (CuO-NPs) were synthesized at 400 °C using a modification of the polymer complex-Pechini method. Considering the procedure used, a mechanism was proposed to explain the formation of CuO-NPs. The synthesized nanoparticles were characterized using IR, Raman and UV–Vis spectroscopies, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicated that the sample synthesized contained CuO as the only crystalline phase, with a crystallite size between 9.17 and 14.95 nm, depending on the crystallographic direction and gap energy values of ∼4 eV and ∼5.86 eV. The CuO powder had agglomerates, in the order of microns, and primary particles smaller than 100 nm, with irregular morphology. The CuO synthetized was not stoichiometric and that it had an excess of oxygen, indicating the presence of cation vacancies and/or interstitial oxygen. The study of the capacity of CuO-NPs to remove methylene blue (MB), without irradiating the system with UV–Vis and without the presence of H₂O₂, showed that these promoted a percent removal of ∼39% in a basic medium (pH ∼9.7).
Catalytic hydrothermal liquefaction of alkali lignin for monophenols production over homologous biochar-supported copper catalysts in water
2023, International Journal of Biological Macromolecules
Constructing an advanced catalytic system for the purposeful liquefaction of lignin into chemicals has presented a significant prospect for sustainable development. In this work, the catalytic process of mesoporous homologous biochar (HBC) derived from alkali lignin supported copper catalysts (Cu/HBC) was reported for catalytic liquefaction of alkali lignin to monophenols. The characterization results revealed HBC promoted the formation of metal-support strong interaction and the generation of oxygen vacancies, enhancing the acid sites of Cu/HBC. Under the optimal conditions (0.2 g alkali lignin, 280 °C, 0.05 g Cu/HBC, 6 h, 18 mL water), the monophenol yield reached 75.01 ± 0.76 mg/g, and the bio-oil yield was 57.98 ± 1.76%. The copious mesopores, high surface area, and rich acidic sites were responsible for the high activity of Cu/HBC, which significantly outperformed the controlled catalysts, such as HBC, commercial activated carbon (AC), and reported Ni/AC, Ni/MCM-41, etc. In four consecutive runs, the catalytic performance of Cu/HBC was only reduced by 3.65% per cycle. Interestingly, catechol was selectively produced with Cu/HBC, which provided an effective strategy for the conversion of G/S-type lignin to catechyl phenolics (C-type). These findings indicate that the Cu/HBC will be a promising substitution of noble metal-supported catalysts for conversion biomass into high value-added phenolics.

View all citing articles on Scopus

View full text

Synthesis of CuO nanorods and their catalytic activity in the thermal decomposition of ammonium perchlorate

Abstract

Introduction

Section snippets

Sample preparation

Results and discussion

Conclusions

Acknowledgments

Prog. Cryst. Growth Charact. Mater.

J. Alloy Compd.

Thermochim. Acta

J. Alloy Compd.

Mater. Lett.

Mater. Lett.

Thermochim. Acta

J. Therm. Anal. Calorim.

J. Catal.

Thermochim. Acta