Surface Passivation of Bare Boron Nanoparticles Using New

Article pubs.acs.org/EF

Surface Passivation of Bare Boron Nanoparticles Using New Dicyanamide-Based Dicationic Ionic Liquid R. Fareghi-Alamdari,*,† F. Ghorbani-Zamani,† and M. Shekarriz‡ †

Faculty of Chemistry and Chemical Engineering, Malek-Ashtar University of Technology, Tehran, Iran Research Institute of Petroleum Industry, West Boulevard, Azadi Sports Complex, Tehran, Iran

‡

ABSTRACT: Boron is traditionally used as an additive in energetic systems as a result of the high density of energy. In particular, the existence of the naturally formed boron oxide (B2O3) layer retards the reactivity by acting as a barrier if it cannot be efficiently removed. In this study, the new dicationic ionic liquid based on dicyanamide anoins was synthesized and used as a protective ligand for boron nanoparticles. The effects of newly synthesized ionic liquid are investigated by a combination of X-ray diffraction (XRD), energy-dispersive X-ray (EDX), scanning electron microscopy (SEM), dynamic light scanning (DLS), ζ-potential measurements, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). It was found that this ionic liquid binds to boron well enough and protects the boron surfaces from oxidation during air exposure. synthesized and reported.14−17 These new types of ILs are considered as solid or melting salts near room temperature. Therefore, they could afford new supramolecules that are suitable for various applications as a result of their high thermal properties and broad liquid range.18−22 These compounds have been studied in different applications, such as high-temperature lubricants,23,24 a solvent for hightemperature organic reactions,23−26 an additive in dye-sensitized solar cells,27 an extraction liquid28 in chromatography29−31 and mass spectroscopy,32 and an electrolyte for secondary batteries.24 Several studies have been performed on the physical properties (e.g., density and viscosity) of DCILs. Most of these properties are dependent upon the struture of DCIL, as is usually the case in monocationic ILs.33,34 Furthermore, the functionalization ability of dicationic ILs explored the opportunity to design their structures with respect to cations, anions, and length of linker chains in between two cations.35−38 Anderson et al. studied the abilities of boron nanoparticles as a high-density additive for dicyanamide-based monocationic IL propellants.9,39 Furthermore, they show that how cationic and anionic structures of ILs play the important roles in the interaction with boron surfaces.9 Despite much effort, most of the research work has thus far focused on monocationic-type energetic ILs. To gain a further understanding of structure−property relations and extend the applications of ILs as energetic and hypergolic components, it is incumbent to explore new dicationic IL structures. In the current study and in continuation of our interest in the synthesis and application of ILs,40,41 here, we report the synthesis and characterization of the new dicationic IL and investigate the effect of this IL on preparing oxide-free and air-stable boron nanoparticles.

1. INTRODUCTION To make fuels more cost-competitive, one of the potential strategies is to increase the energy density by adding higher energy density additives. Nanosized metal powders have been considered as potential fuel additives as a result of their high specific surface area and ability to store energy on the surface. Among various metals considered as additives for fuels and propellants, the highest combustion enthalpies are seen for aluminum, boron, beryllium, magnesium, etc.1 Of these, boron has the highest volumetric heating value as well as second highest on a gravimetric basis, after the toxic beryllium.2 Despite the desirable properties of boron, the incorporation of boron nanoparticles into the propellants is not widely practiced, because of its oxidation product B2O3. The boron particles combustion occurs in two successive steps: the first step involves the removal of the oxide layer, while the second involves the burning of bare boron.3 The pre-existing oxide layer on the boron surface plays an important role in the ignition and combustion processes; more precisely, it delays the ignition process. Various methods have been conducted to mitigate the effects of the oxide layer and enhance the ignition of boron nanoparticles, including the following:4−11 (1) treating boron particles with TiCl4 and triethylaluminum followed by the addition of ethylene or even coating boron particles with LiF and trimethylolpropane, (2) sodium naphtalenid reduction of BBr3 in 1,2-dimethoxyethene followed by n-octanol, (3) coating of boron particles with metals, such as titanium and Mg, (4) utilization of energetic materials, such as glycidyl azide polymer (GAP) and azide polymer (AP), coating on the boron surface, and (5) capping boron particles with an organic oleic acid layer. Recently, ionic liquids (ILs), which are organic salts with a melting point below 100 °C, were used as capping agents for boron particles.9 ILs have unique properties, such as low-vapor pressure, liquidity over a wide temperature range, high density, high thermal and chemical stabilities, and structural design ability.12,13 Dicationic ionic liquids (DCILs), a type of IL, in which two monocations are combined into a dication have been recently © XXXX American Chemical Society

Received: July 10, 2015 Revised: December 4, 2015

A

DOI: 10.1021/acs.energyfuels.5b01556 Energy Fuels XXXX, XXX, XXX−XXX

Article

Energy & Fuels Scheme 1. Multistep Synthetic Route of Dicyanamide-Based DCIL2

Figure 1. XRD patterns of (A) boron-milled powders and (B) DCIL2-capped boron sample. B


Article

Energy & Fuels

Figure 2. EDX spectra of (A) boron-milled powders and (B) DCIL2-capped boron sample. were dimethyl sulfoxide (DMSO) and deuterium oxide (D2O). Fourier transform infrared (FTIR) spectra were obtained on a Nicolet 800 instrument. Elemental analyses were obtained using a Heraeous CHN analyzer and energy-dispersive X-ray (EDX, Tescan Vega 3). Thermal behavior and decomposition temperatures were measured using thermogravimetric analysis (TGA, Pyris diamond, PerkinElmer) at a heating rate of 20 °C/min. To investigate the thermal profile of the IL and boron-loaded IL, samples of 10−25 mg were analyzed on a platinum pan under a purge of oxygen and measured via dynamic heating. Samples were heated from room temperature to 1000 °C. The crystallographic structures of compounds were identified by X-ray diffraction (XRD, Philips PW3710), and then, the crystallinity was calculated. Scanning electron microscopy (SEM, FEI Zeiss, Sigma) and dynamic light scanning (particle sizing system, Microtrac, Nanotrac Wave) analyses were performed to examine the particle size distributions. X-ray photoelectron spectroscopy (XPS) measurements were performed on a SSX-100 system (Surface Science Laboratories, Inc.) equipped with a monochromated Al Ka X-ray source, a hemispherical sector analyzer, and a resistive anode detector. The base pressure of the XPS system was 5.0 × 10−10 Torr. During the data collection, the pressure equaled ∼5 × 10−9 Torr. The X-ray spot size was 1 × 1 mm2, corresponding to an X-ray power of 200 W. The high-resolution spectra were collected using 50 eV pass energy and 0.1 eV/step. The ESCA 2005 software provided with the XPS system was used for data processing. 2.2. Synthesis Procedure. 2.2.1. Synthesis of N-(2-Hydroxyethyl)-N,N,N-trimethylammonium Iodide (I). To a stirred solution

With regard to the selection of the energetic anion, the dicyanamide anion provides a combustible organic structure and gives ILs with low viscosities, wide liquid ranges, and its important role in the interaction with boron surfaces.42,9 On the other hand, the introduction of fuel-rich amine groups into the cations can increase the energy density and hypergolic reactivity of the resultant energetic ILs.43 Therefore, open-chain amines and dicyanamide anion were chosen for the preparation of the new dicationic IL. In addition to the synthesis of novel dicyanamide dicationic IL, we added high energy density boron nanoparticles as an additive, which does not interfere with the desired IL traits, such as low or negligible vapor pressure. On the other hand, intercalation of boron nanoparticles into the synthesized DCIL can protect the boron nanoparticle surfaces from unwanted oxidation and also promote its suspension in a variety of fuels.

2. EXPERIMENTAL SECTION 2.1. Reagents and Instruments. 2-(Dimethylamino)ethanol, methylimidazole, thionyl chloride, 1-vinylimidazole, silver nitrate, sodium dicyanamide, micrometer-sized boron powder (97%, 2 μm particles), and all organic solvents were analytical reagents purchased from commercial sources and used as received. 1 H and 13C nuclear magnetic resonance (NMR) were recorded on a Bruker DRX 300 spectrometers. Chemical shifts were reported relative to tetramethylsilane (TMS) as an internal standard. The solvents used C


Article

Energy & Fuels

Figure 3. SEM images for (A) boron-milled powders and (B) DCIL2-capped boron sample. 2.2.2. Synthesis of N-(2-Chloroethyl)-N,N,N-trimethylammonium Chloride (II). To a stirred solution of ammonium-based salt obtained from a previous step (10 mmol, 2.31 g) in chloroform (20 mL) was added thionyl chloride (12.5 mmol, 1.47 mL) dropwise at 0−5 °C. The reaction mixture was stirred for 4−5 h at 65 °C. After this step, the product was obtained by evaporation of chloroform. The crude product was purified by dissolving it in boiling ethanol, and then the impurities were separated by filtering. Ethanol was removed from the mixture by vacuum evaporation at 60 °C. Finally, the resulting yellow salt was dried under vacuum at 80 °C for 3 h (mp of 228−230 °C and yield of 86%). The second step of Scheme 1 represents the synthesis of salt II. Spectroscopic data for salt II: 1H NMR (300 MHz, DMSO) δ: 4.08 (t, 2H, J = 6 Hz), 3.79 (t, 2H, J = 6.23 Hz), 3.18 (s, 9H, CH3).

of 2-(dimethylamino)ethanol (10 mmol, 0.89 g) in acetonitrile (20 mL) was added methyl iodide (12 mmol, 17.04 g) dropwise at 0−5 °C. The reaction mixture was stirred for 12 h at 60 °C. Removal of the solvent under reduced pressure afforded crude ammonium-based salt. The crude product was purified by salting out in the mixture of acetonitrile and n-hexane. Finally, the resulting white salt was dried under vacuum at 80 °C for 5 h [melting point (mp) of 272−274 °C and yield of 90%]. The first step of Scheme 1 represents the synthesis of salt I. Spectroscopic data for salt I: 1H NMR (300 MHz, D2O) δ: 3.67 (t, 2H, J = 5.1 Hz), 3.37 (t, 2H, J = 5.0 Hz), 3.10 (s, 9H, CH3). 13 C NMR (75 MHz, D2O) δ: 56.51, 42.11, 40.32. IR (KBr, ν, cm−1): 3396, 2957, 1488, 1385, 1048, 752. Anal. Calcd for C5H14INO: C, 25.96; H, 6.06; N, 6.06%; found: C, 25.90; H, 5.99; N, 5.97%. D


Article

Energy & Fuels C NMR (75 MHz, D2O) δ: 64.77, 52.58, 40.33. IR (KBr, ν, cm−1): 3382, 2972, 1486, 1302, 1245, 731. Anal. Calcd for C5H13ClIN: C, 23.98; H, 5.17; N, 5.57%; found: C, 24.00; H, 5.21; N, 5.61%. 2.2.3. Synthesis of 3-(N,N,N-Trimethylammonio)ethyl-1-vinyl-1H-imidazol-3-ium Chloride Iodide (DCIL1). 1-Vinylimidazole (12 mmol, 1.13 g) was slowly added to an ammonium-based salt (II) (10 mmol, 2.49 g) in acetonitrile (20 mL). The reaction mixture was stirred for 20 h at 70 °C to form DCIL1. The DCIL1 mass was washed 3 times with a mixture of acetonitrile and ethyl acetate. After being under vacuum at 80 °C for 5 h, the light brown liquid crystalline was obtained (yield of 88%). The third step of Scheme 1 represents the synthesis of DCIL1. Spectroscopic data for DCIL1: 1H NMR (300 MHz, D2O) δ: 8.93 (s, 1H, CH), 7.66 (d, 1H, J = 2 Hz), 7.41 (d, 1H, J = 2.11 Hz), 6.96 (m, 1H, CH), 5.61 (dd, 1H, CH), 5.26 (dd, 1H, CH), 3.84 (t, 2H, J = 6 Hz), 3.66 (t, 2H, J = 6 Hz), 3.01 (s, 9H, CH3). 13 C NMR (75 MHz, D2O) δ: 126.78, 121.77, 119.27, 117.9, 109.52, 66.05, 35.46, 42.97. IR (KBr, ν, cm−1): 3384, 3010, 2972, 1628, 1488, 1302, 731. Anal. Calcd for C10H19N3: C, 34.87; H, 5.48; N, 12.17%; found: C, 34.92; H, 5.53; N, 12.22%. 2.2.4. Synthesis of 3-(N,N,N-Trimethylammonio)ethyl-1-vinyl-1H-imidazol-3-ium Didicyanamide (DCIL2). Silver dicyanamide was prepared by mixing equal molar amounts of silver nitrate and sodium dicyanamide in aqueous solution followed by filtration. Then, to a solution of DCIL1 (10 mmol, 3.43 g) in distilled water (20 mL) was added silver dicyanamide (20 mmol, 3.48 g). The reaction mixture was stirred for 24 h at 40 °C. After that, the reaction mixture was cooled at room temperature. The solution was filtered to remove any precipitate of silver halide salt, and the filtrate was dried under vacuum. The brown liquid crystalline was then washed with diethyl ether and dried under vacuum for 24 h (yield of 95%). The fourth step of Scheme 1 shows the anion-exchange reaction and synthesis of final ILs. Synthesis of 3-(N,N,N-trimethylammonio)ethyl-1-vinyl-1-H-imidazol-3-ium didicyanamide (DCIL2): 1H NMR (300 MHz, D2O) δ: 8.28 (s, 1H, CH), 7.84 (d, 1H, J = 2.99 Hz), 7.69 (d, 1H, J = 2.83 Hz), 7.10 (m, 1H, CH), 5.84 (dd, 1H, CH), 5.79 (dd, 1H, CH), 3.95 (t, 2H, J = 7.5 Hz), 3.71 (t, 2H, J = 7.32 Hz), 3.17 (s, 9H, CH3). 13 C NMR (75 MHz, D2O) δ: 127.78, 127.79, 120.12, 120.01, 119.79, 110.25, 66.13, 35.49, 42.96. IR (KBr, ν, cm−1): 3495, 3012, 2233, 2190, 2134, 16.53, 1555, 1482, 1314, 1176. Anal. Calcd for C14H19N9: C, 53.62; H, 6.07; N, 40.25%; found: C, 53.71.92; H, 6.15; N, 40.28%. 2.3. Boron Milling Process. Commercial boron powder was used as the starting material in a milling process. Particle size reduction was performed using a Certipres 8000 mixer mill with tungsten carbide milling jars and 1/8 in. diameter balls of the same material as the jar. For hard materials, such as boron, the hardness of tungsten carbide helps both the milling speed and resisting abrasion. Also, to avoid possible reaction of boron surfaces with oxygen or even nitrogen, the dry milling was performed under a pure argon atmosphere by loading and sealing the jar in an Ar-filled glovebox. A two-step milling process was employed. First, 0.9 g of boron (30 wt %) was dry-milled with 30.0 g of tungsten carbide balls under an Ar atmosphere for 3 h. Then, in a second step, the jar was opened, 2.1 g of the synthesized DCIL2 was added, and an additional 3 h of milling was performed. After milling, the boron−DCIL2 mixture was removed using ethanol as the solvent. The mixture was washed 3 times with ethanol and dried under reduced pressure. Opening and closing of the milling jar for the addition of reagents were performed inside the Ar-filled glovebox.

for 3 h and then mixed by DCIL2 for another 3 h in a milling jar (it is noticeable that both samples were kept at room temperature for 3 weeks, and then XRD analysis was performed). Figure 1 shows that samples have some obvious diffraction peaks of crystalline compounds at 2θ of 38°, 65°, 73°, 77°, and 85°, which are attributed to the impurities of magnesium borate and tungsten carbide. By comparison of XRD patterns of samples A and B, a district peak at 2θ = 27° can be seen, confirming the presence of crystalline B2O3. After 3 weeks, the oxide layer crystallized on the surface of milled boron was produced (sample A) and the corresponding peak was detected on its XRD pattern. In contrast, there is no obvious peak of crystalline boron oxide in sample B, which indicated the capping boron surface with the DCIL2 layer that prevents oxidation of boron surfaces. 3.2. EDX Analysis. Figure 2 shows the EDX spectrum of the milled boron powders and DCIL2-capped boron samples. EDX analysis confirmed that the milled boron powders consist of boron and oxygen with a small amount of Mg and W, while EDX analysis of DCIL-capped boron samples determined the presence of boron, carbon, nitrogen, and a small amount of oxygen, with Mg and W apparently coming from DCIL2 and impurities, such as Mg, WC, or even MgO or Mg3B2O3. These results are in good agreement with the results obtained from XRD analysis. 3.3. Particle Properties. Figures 3 and 4 show that the size distributions were determined by SEM and DLS measurements,

3. RESULTS AND DISCUSSION In this study, dicyanamide-based dicationic IL was synthesized using a multistep synthetic route (Scheme 1). The structures of all synthesized compounds were elucidated using FT−NMR and FTIR spectrometries as well as elemental analysis. 3.1. XRD Pattern. Figure 1 shows XRD patterns of the amorphous boron powders prepared in different conditions. For sample A, the boron powders were prepared by milling 3 h in an Ar atmosphere. For sample B, boron particles were milled

respectively. SEM images were employed to observe the microstructure of nanoparticles, which provide a better view of the boron particle size. As seen from SEM images, boron nanoparticles have a broad size distribution in different samples. For the boron-milled sample (Figure 3A), an average size is about 28.8 nm (standard deviation of 8.01), while an average particle size for the DCIL2-capped boron sample (Figure 3B) is about 45.36 nm (standard deviation of 12.86). Moreover, The DLS measurements showed that the milling procedure generated boron particles mostly in the 60−80 nm

13

Figure 4. DLS measurement of (A) boron-milled powders and (B) DCIL2-capped boron sample.

E


Article

Energy & Fuels

Figure 5. B 1s XPS regional spectrum of boron nanoparticles: (A) unwashed DCIL2-capped boron and (B) washed DCIL2-capped boron samples.

with a dense enough layer of DCIL2, which prevents oxidation of boron particles during air exposure. 3.5. FTIR Analysis. Additional insight into the binding of DCIL2 to boron surfaces was provided by infrared spectroscopy. Figure 5 depicts spectra of neat DCIL2 and boron-capped samples. The strongest spectra feature for dicyanamide anionbased ILs is a group of three peaks at 2246 cm−1 (symmetric CN stretch), 2193 cm−1 (overlapping symmetric and asymmetric C−N), and 2126 cm−1 (asymmetric CN stretch), which have been assigned as vibrations of the dicyanamide anion.45 With regard to this, it can be seen from Figure 6 that peak intensities of symmetric CN stretch and C−N stretching bands decreased substantially compared to the asymmetrical CN stretching band in the DCIL-capped boron sample. In addition, the C−H stretch from methyl groups was observed in the 3000−3100 cm−1 region for DCIL2. In the DCIL2capped boron sample, the C−H stretches are nearly absent. These phenomena indicated that synthesized DCIL successfully bonded on boron surfaces.9 These evidently confirm the results of XRD and EDX analyses and show that the DCIL2 layer exists on the boron nanoparticle surfaces.

size range (Figure 4A), while boron milled with DCIL2 generated particles mostly in the 100−150 nm size range that probably result from aggregates of smaller primary particles (Figure 4B). By comparison of the SEM and DLS images of boron powders and DCIL-capped boron, it can be found that the agglomeration happened more in the presence of DCIL2. The reunion phenomena appear in sample B, as a result of the specific surface area and reactivity of boron surfaces with the DCIL2 structure. 3.4. XPS Analysis of the DCIL2-Capped Boron Sample. A high-resolution XPS scan in the B 1s range is shown in Figure 5. A comparison of XPS for the unwashed sample (Figure 5A) to the washed DCIL2-capped boron sample (Figure 5B) shows that, in the unwashed sample, two boron chemical states are observed. The most intense peak, located at 188.5 eV, is assigned to elemental boron. Previous studies on B2O3 have reported peaks centered around 193 eV. Therefore, it is reasonable to attribute the peak at 193 eV to boron oxide.7 The absence of a 193 eV peak in the washed sample probably indicates that small particles tend to be lost in the washing process used to remove excess DCIL2 from the particles. In addition, this shows that washed particles must still be coated F


Article

Energy & Fuels

Figure 6. FTIR spectra of (A) neat DCIL2 and (B) DCIL2-capped boron samples.

by the anionic structure of IL. Hence, the negative ζ potentials (−10.6 mV) for milled oxidized boron and (−23.9 mV) for DCIL2/boron samples confirm that boron surface oxidation and a strongly bound layer are dominated by the dicyanamide anion in these samples, respectively. 3.7. TGA. As a final way of examining DCIL2−boron coordination, TGA was used to investigate the thermal stability of the DCIL2 layer. The main goal of coating boron particles with ILs is to prevent oxidation of boron surfaces in ambient air, but oxidation must occur efficiently at higher temperatures to allow for boron ignition. Therefore, we studied the thermal behavior of neat DCIL2 and boron particles capped by DCIL2 in an oxygen atmosphere.

3.6. ζ-Potential Measurements. ζ-potential measurement is one of the ways of examining how salts and ILs bind to nanoparticle surfaces.44 ζ potential is sensitive to the net charge of the ionic species binding on the surface. Figure 7 shows the ζ potentials measured for boron nanoparticles prepared in different conditions using acetonitrile as an aprotic solvent. Anderson et al. previously reported that the ζ potential of boron milled in acetonitrile with no ligand and without exposure to oxygen is essentially 0 (−1.0 ± 2.5 mV), while the milled oxidized boron showed ζ potential at about −10.0 ± 3.5 mV.9 They also showed that ILs linked to boron surfaces by their cationic counterpart have positive ζ potentials. However, a negative ζ potential suggests that the protective layer is dominated G


Article

Energy & Fuels

Figure 7. ζ-potential measurement of (A) boron-milled powder and (B) DCIL2-capped boron samples.

Figure 8. TGA curve of (A) neat DCIL2 and (B) DCIL2-capped boron samples.

started to decompose from 207 to 293 °C, as observed in Figure 8A. Thus, the thermal behavior of DCIL2-capped boron in an oxygen atmosphere is closely dependent upon the decomposition of dicyanamide anions. After thermal decomposition of the DCIL2 layer, the rapid mass gain was observed, which indicates oxide layer formation on the boron nanoparticle surfaces.

As seen from Figure 8A, the synthesized DCIL2 mass losses occurred in two steps. The initial 33% at 207 °C is comparable to the stoichiometric mass percentage of the dicyanamide anion (∼42%). Therefore, it is possible to claim that first the anion and then the cation decompose in the dicationic IL studied. For DCIL2-capped boron, the mass loss was observed at 220 °C, associated with the loss of the DCIL2 layer, following the mass gain associated with boron particle oxidation (Figure 8B). It is then important to highlight that the IL structures could modify the beginning of the boron oxidation. In this work, dicyanamide anions

4. CONCLUSION The DCIL with the dicyanamide anion was synthesized successfully using a multistep synthetic route. Boron nanoparticles and H


Article

Energy & Fuels

(23) Jin, C. M.; Ye, C.; Phillips, B. S.; Zabinski, J. S.; Liu, X.; Liu, W.; Shreeve, J. M. J. Mater. Chem. 2006, 16, 1529−1535. (24) Han, X.; Armstrong, D. W. Org. Lett. 2005, 7, 4205−4208. (25) Xiao, J. C.; Shreeve, J. M. J. Org. Chem. 2005, 70, 3072−3078. (26) Zafer, C.; Ocakoglu, K.; Ozsoy, C.; Icli, S. Electrochim. Acta 2009, 54, 5709−5714. (27) Cao, Y.; Mu, T. Ind. Eng. Chem. Res. 2014, 53, 8651−8664. (28) Visser, A. E.; Holbrey, J. D.; Rogers, R. D. Chem. Commun. 2001, 2484−2485. (29) Huang, K.; Han, X.; Zhang, X.; Armstrong, D. W. Anal. Bioanal. Chem. 2007, 389, 2265−2275. (30) Anderson, J. L.; Armstrong, D. W. Anal. Chem. 2005, 77, 6453− 6462. (31) Qi, M.; Armstrong, D. W. Anal. Bioanal. Chem. 2007, 388, 889− 899. (32) Soukup-Hein, R. J.; Remsburg, J. W.; Dasgupta, P. K.; Armstrong, D. W. Anal. Chem. 2007, 79, 7346−7352. (33) Anderson, J. L.; Ding, R.; Ellern, A.; Armstrong, D. W. J. Am. Chem. Soc. 2005, 127, 593−604. (34) Zeng, Z.; Phillips, B. S.; Xiao, J. C.; Shreeve, J. M. Chem. Mater. 2008, 20, 2719−2726. (35) Misuk, V.; Breuch, D.; Löwe, H. Chem. Eng. J. 2011, 173, 536− 540. (36) Domańska, U.; Lukoshko, E. V.; Królikowski, M. Chem. Eng. J. 2012, 183, 261−270. (37) Li, X.; Bruce, D. W.; Shreeve, J. M. J. Mater. Chem. 2009, 19, 8232−8238. (38) Kore, R.; Srivastava, R. J. Mol. Catal. A: Chem. 2011, 345, 117− 126. (39) Visser, A. E.; Swatloski, R. P.; Reichert, W. M.; Mayton, R.; Sheff, S.; Wierzbicki, A.; Davis, J. H.; Rogers, R. D. Environ. Sci. Technol. 2002, 36, 2523−2529. (40) Fareghi-Alamdari, R.; Ghorbani-Zamani, F.; Zekri, N.; Kozehgari, G. J. Iran. Sci. Assoc. Energy Mater. 2012, 7, 17−25. (41) Fareghi-Alamdari, R.; Ghorbani-Zamani, F.; Zekri, N. J. Serb. Chem. Soc. 2014, 79, 1337−1346. (42) Brand, A. J.; Drake, G. U.S. Patent 6,218,577 B1, April 17, 2001. (43) Zhang, Y.; Gao, H.; Joo, Y. H.; Shreeve, J. M. Angew. Chem., Int. Ed. 2011, 50, 9554−9562. (44) Lotsch, B. V.; Senker, J.; Kockelmann, W.; Schnick, W. J. Solid State Chem. 2003, 176, 180−191. (45) Delgado, A. V.; González-Caballero, F.; Hunter, R. J.; Koopal, L. K.; Lyklema, J. Pure Appl. Chem. 2005, 77, 1753−1805.

DCIL2-capped boron were produced using a ball mill technique with size distributions of 50−100 nm, as shown by DLS and SEM measurements. The results of XRD, EDX, FTIR, XPS, and ζ-potential measurements showed that boron nanoparticle surfaces were successfully capped by the DCIL2 layer, which protects the boron surfaces against the air oxidation. TGA measurements showed that the nanoparticle oxidation occurred after DCIL2 thermal decomposition and allows for boron ignition at higher temperatures.

■

AUTHOR INFORMATION

Corresponding Author

*Telephone: +98-937-3381632. Fax: +98-21-44658251. E-mail: [email protected]. Notes

The authors declare no competing financial interest.

■ ■

ACKNOWLEDGMENTS The authors are grateful to Malek-Ashtar University of Technology for supporting this work. REFERENCES

(1) Dreizin, E. L. Prog. Energy Combust. Sci. 2009, 35, 141−167. (2) Wang, J.; Gu, Y.; Li, Z.; Wang, W.; Fu, Z. Mater. Res. Bull. 2013, 48, 2018−2022. (3) Mačeic, A.; Semple, J. M. Combust. Sci. Technol. 1969, 1, 181− 191. (4) Dubois, C.; Brousseau, P.; Roy, C.; Lafleur, P. Proceedings of the AIChE Annual Meeting; Austin, TX, Nov 7−12, 2004; pp 281E/1− 281E/9. (5) Pickering, A. L.; Mitterbauer, C.; Browning, N. D.; Kauzlarich, S. M.; Power, P. P. Chem. Commun. 2007, 580−582. (6) Van Devener, B.; Perez, J. P. L.; Anderson, S. L. J. Mater. Res. 2009, 24, 3462−3464. (7) Van Devener, B.; Perez, J. P. L.; Jankovich, J.; Anderson, S. L. Energy Fuels 2009, 23, 6111−6120. (8) Perez, J. P. L.; McMahon, B. W.; Anderson, S. L. J. Propul. Power 2013, 29, 489−495. (9) Perez, J. P. L.; McMahon, B. W.; Schneider, S.; Boatz, J. A.; Hawkins, T. W.; McCrary, P. D.; Beasley, P. A.; Kelley, S. P.; Rogers, R. D.; Anderson, S. L. J. Phys. Chem. C 2013, 117, 5693−5707. (10) Perez, J. P. L.; Yu, J.; Sheppard, A. J.; Chambreau, S. D.; Vaghjiani, G. L.; Anderson, S. L. ACS Appl. Mater. Interfaces 2015, 7, 9991−10003. (11) Anderson, J. L.; Ding, R.; Ellern, A.; Armstrong, D. W. J. Am. Chem. Soc. 2005, 127, 593−604. (12) Ghandi, K. Green Sustainable Chem. 2014, 04, 44−53. (13) Ben Ghanem, O.; Mutalib, M. I. A.; Lévêque, J. M.; Gonfa, J.; Kait, C. F.; El-Harbawi, M. J. Chem. Eng. Data 2015, 60, 1756−1763. (14) Brown, P.; Butts, C. P.; Eastoe, J.; Padrón Hernández, E.; Machado, F. L. A.; de Oliveira, R. J. Chem. Commun. 2013, 49, 2765− 2767. (15) Chang, J. C.; Ho, W. Y.; Sun, I. W.; Tung, Y. L.; Tsui, M. C.; Wu, T. Y.; Liang, S. S. Tetrahedron 2010, 66, 6150−6155. (16) Shirota, H.; Mandai, T.; Fukazawa, H.; Kato, T. J. J. Chem. Eng. Data 2011, 56, 2453−2459. (17) Han, X.; Armstrong, D. W. Org. Lett. 2005, 7, 4205−4208. (18) Priede, E.; Nakurte, I.; Zicmanis, A. Synth. Commun. 2014, 44, 1803−1809. (19) Li, S.; Feng, G.; Cummings, P. T. J. Phys.: Condens. Matter 2014, 26, 284106−284116. (20) Chowdhury, S.; Mohan, R. S.; Scott, J. L. Tetrahedron 2007, 63, 2363−2389. (21) Hallett, J. P.; Welton, T. Chem. Rev. 2011, 111, 3508−3576. (22) Song, X.; Vig, B. S.; Lorenzi, P. L.; Drach, J. C.; Townsend, L. B.; Amidon, G. L. J. Med. Chem. 2005, 48, 1274−1277. I


Surface Passivation of Bare Boron Nanoparticles Using New

Recommend Documents