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Boron nitride encapsulated copper nanoparticles: a facile one-step synthesis and their effect on thermal decomposition of ammonium perchlorate.

Huang C, Liu Q, Fan W, Qiu X - Sci Rep (2015)

Bottom Line: Here, we developed an alternative approach to encapsulate copper nanoparticles with a chemical inertness material--hexagonal boron nitride.The wrapped copper nanoparticles not only exhibit high oxidation resistance under air atmosphere, but also keep excellent promoting effect on thermal decomposition of ammonium perchlorate.This approach opens the way to design metal nanoparticles with both high stability and reactivity for nanocatalysts and their technological application.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou 350002, P. R. China.

ABSTRACT
Reactivity is of great importance for metal nanoparticles used as catalysts, biomaterials and advanced sensors, but seeking for high reactivity seems to be conflict with high chemical stability required for metal nanoparticles. There is a subtle balance between reactivity and stability. This could be reached for colloidal metal nanoparticles using organic capping reagents, whereas it is challenging for powder metal nanoparticles. Here, we developed an alternative approach to encapsulate copper nanoparticles with a chemical inertness material--hexagonal boron nitride. The wrapped copper nanoparticles not only exhibit high oxidation resistance under air atmosphere, but also keep excellent promoting effect on thermal decomposition of ammonium perchlorate. This approach opens the way to design metal nanoparticles with both high stability and reactivity for nanocatalysts and their technological application.

No MeSH data available.


Related in: MedlinePlus

(a) DTA of AP decomposition in the presence of the as-obtained samples, (b) heat release during the exothermic process occurred in (a).
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f5: (a) DTA of AP decomposition in the presence of the as-obtained samples, (b) heat release during the exothermic process occurred in (a).

Mentions: Following the above analysis, the Cu@h-BN composites with various Cu contents are initially used as the additives to promote the thermal decomposition of AP with and attempt to study the the reactivity of the Cu nanoparticles stabilized by h-BN. Since the thermal decompostion of AP can be greatly influenced by the sizes and morphologies of AP46, the SEM observation of the AP was conducted. As shown in Fig. 3d, the AP exhibits a inhomogeneity in sizes ranging from hundreds nanometer to about 10 um. Differential thermal analysis (DTA) and heat release analyses have been carried out to study the promoting effects of the Cu@h-BN composites on the thermodynamic behavior of the AP (the samples Cu@h-BN: AP = 2: 98 wt/wt) during the reaction at a heating rate of 10 °C/min. As for AP alone (Fig. 5a), one endothermic peak at 246 °C is observed, which comes from the phase transition from orthorhombic to cubic form46, while two exothermic peaks located at the range of 280 to 450 °C orginate from the AP decomposition. The small exothermic peak at 307 °C corresponds to low temperature decomposition resulting from the partial decomposition of AP, and another broad peak at 391 °C is attributed to the complete decomposition47. The decomposition of AP seems to be hindered by the addition of pure h-BN, implying the h-BN can not act as a good promoter for the AP decomposition. This is probably due to the electric insulating of h-BN disfavoring charge transfer occurred during the AP decomposition process46. Encouragingly, with the addition of the Cu@h-BN samples, the exothermic peaks for the complete decomposition of AP become sharper and shift to lower temperature, despite of no significant changes on the phase transition of AP. This implies that our Cu@h-BN samples can trigger complete decomposition at lower temperature and promote its decomposition process. Moreover, the remarkable decrease of complete decomposition temperature leads to that the two exothermic peaks tend to be integrated into an exothermic peak, which is beneficial for the heat release of AP and its practical application as the propellants. The promoting effect of Cu@h-BN samples first increase with the Cu content up to 25.0 wt%, and decrease with further increasing the Cu content to 30.7 wt%. Among all the samples, Cu@h-BN sample with 25.0 wt% is found to be most active. The promoting effect could be explained by that the decomposition products NH3 and HClO4 are absorbed on the additive surface and initiate their subsequent redox reaction47, which will be discussed below. Moreover, we also investigated heat release for AP decomposition to get more details on the promoting effects of Cu@h-BN samples. Figure 5b demonstrates that the presence of the Cu@h-BN samples can lead to much more heat release than AP alone. the overall heat releases are determined to be 1339, 1270, 1485, 1578, 1552, 1820 and 1633 J/g for AP alone and AP with the addition of Cu@h-BN samples, respectively, demonstrating that the decomposition of AP is advanced by the Cu@h-BN samples, especially by Cu@h-BN with 25.0 wt% Cu content (1820 J/g). Moreover, we have compared the activity of fresh Cu@h-BN samples with 25.0 wt% Cu content and the one stored in air atmosphere for three months. From Fig. S6, the similar DTA curves are observed for the fresh sample and the stored one, further confirming the high stability of Cu@h-BN samples.


Boron nitride encapsulated copper nanoparticles: a facile one-step synthesis and their effect on thermal decomposition of ammonium perchlorate.

Huang C, Liu Q, Fan W, Qiu X - Sci Rep (2015)

(a) DTA of AP decomposition in the presence of the as-obtained samples, (b) heat release during the exothermic process occurred in (a).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4645124&req=5

f5: (a) DTA of AP decomposition in the presence of the as-obtained samples, (b) heat release during the exothermic process occurred in (a).
Mentions: Following the above analysis, the Cu@h-BN composites with various Cu contents are initially used as the additives to promote the thermal decomposition of AP with and attempt to study the the reactivity of the Cu nanoparticles stabilized by h-BN. Since the thermal decompostion of AP can be greatly influenced by the sizes and morphologies of AP46, the SEM observation of the AP was conducted. As shown in Fig. 3d, the AP exhibits a inhomogeneity in sizes ranging from hundreds nanometer to about 10 um. Differential thermal analysis (DTA) and heat release analyses have been carried out to study the promoting effects of the Cu@h-BN composites on the thermodynamic behavior of the AP (the samples Cu@h-BN: AP = 2: 98 wt/wt) during the reaction at a heating rate of 10 °C/min. As for AP alone (Fig. 5a), one endothermic peak at 246 °C is observed, which comes from the phase transition from orthorhombic to cubic form46, while two exothermic peaks located at the range of 280 to 450 °C orginate from the AP decomposition. The small exothermic peak at 307 °C corresponds to low temperature decomposition resulting from the partial decomposition of AP, and another broad peak at 391 °C is attributed to the complete decomposition47. The decomposition of AP seems to be hindered by the addition of pure h-BN, implying the h-BN can not act as a good promoter for the AP decomposition. This is probably due to the electric insulating of h-BN disfavoring charge transfer occurred during the AP decomposition process46. Encouragingly, with the addition of the Cu@h-BN samples, the exothermic peaks for the complete decomposition of AP become sharper and shift to lower temperature, despite of no significant changes on the phase transition of AP. This implies that our Cu@h-BN samples can trigger complete decomposition at lower temperature and promote its decomposition process. Moreover, the remarkable decrease of complete decomposition temperature leads to that the two exothermic peaks tend to be integrated into an exothermic peak, which is beneficial for the heat release of AP and its practical application as the propellants. The promoting effect of Cu@h-BN samples first increase with the Cu content up to 25.0 wt%, and decrease with further increasing the Cu content to 30.7 wt%. Among all the samples, Cu@h-BN sample with 25.0 wt% is found to be most active. The promoting effect could be explained by that the decomposition products NH3 and HClO4 are absorbed on the additive surface and initiate their subsequent redox reaction47, which will be discussed below. Moreover, we also investigated heat release for AP decomposition to get more details on the promoting effects of Cu@h-BN samples. Figure 5b demonstrates that the presence of the Cu@h-BN samples can lead to much more heat release than AP alone. the overall heat releases are determined to be 1339, 1270, 1485, 1578, 1552, 1820 and 1633 J/g for AP alone and AP with the addition of Cu@h-BN samples, respectively, demonstrating that the decomposition of AP is advanced by the Cu@h-BN samples, especially by Cu@h-BN with 25.0 wt% Cu content (1820 J/g). Moreover, we have compared the activity of fresh Cu@h-BN samples with 25.0 wt% Cu content and the one stored in air atmosphere for three months. From Fig. S6, the similar DTA curves are observed for the fresh sample and the stored one, further confirming the high stability of Cu@h-BN samples.

Bottom Line: Here, we developed an alternative approach to encapsulate copper nanoparticles with a chemical inertness material--hexagonal boron nitride.The wrapped copper nanoparticles not only exhibit high oxidation resistance under air atmosphere, but also keep excellent promoting effect on thermal decomposition of ammonium perchlorate.This approach opens the way to design metal nanoparticles with both high stability and reactivity for nanocatalysts and their technological application.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou 350002, P. R. China.

ABSTRACT
Reactivity is of great importance for metal nanoparticles used as catalysts, biomaterials and advanced sensors, but seeking for high reactivity seems to be conflict with high chemical stability required for metal nanoparticles. There is a subtle balance between reactivity and stability. This could be reached for colloidal metal nanoparticles using organic capping reagents, whereas it is challenging for powder metal nanoparticles. Here, we developed an alternative approach to encapsulate copper nanoparticles with a chemical inertness material--hexagonal boron nitride. The wrapped copper nanoparticles not only exhibit high oxidation resistance under air atmosphere, but also keep excellent promoting effect on thermal decomposition of ammonium perchlorate. This approach opens the way to design metal nanoparticles with both high stability and reactivity for nanocatalysts and their technological application.

No MeSH data available.


Related in: MedlinePlus