Ammonium Perchlorate Decomposition in Nano-titania

Ammonium Perchlo score Decomposition in Nano-titaniaThermal buncombe of ammonium ion ion ion ion perchlorate in the front of commercial nano-titaniaMostafa Mahinroosta*AbstractAddition of coat and coat oxide nanoparticles ( specially transition metallic element oxides) to ammonium perchlorate improves its caloric decline via decreasing the gamy temperature of guff. Two mechanisms including electron- convert and proton-transfer take for been proposed for thermal dissolution of ammonium perchlorate. In this enquiry field, nm transition metal oxides take up attracted a growing attention. te dioxide exists chthonic three gossamer forms of rutile, anatase, and brookite. All three forms occur naturally but the latter is rather r atomic number 18 and has no commercial interest. Anatase becomes to a greater extent stable than rutile when the particle coat is decreased below 14 nm. In the present study, commercial nano-titania with an average particle sizing of 10-25 n m was added to ammonium perchlorate. catalytic upshot of the titania nanoparticles on the thermal bunk of ammonium perchlorate was evaluated. Some samples of ammonium perchlorate consisting of sundry(a) mass loadings of nano-titania were prepargond. Thermogravimetry analysis results indicate that accompaniment of titania nanoparticles to ammonium perchlorate slightens decay temperature of ammonium perchlorate. The most decrease in the decomposition temperature was 61 C and observed in the presence of 3 wt.% of nanometer atomic number 22 dioxide.Keywords Titania Ammonium perchlorate Thermal decomposition Nanostructure.1. mental hospitalOver the past few years, nanoparticles of many incompatible compounds and combinations find genuine considerable attention in the scientific and engineering research handle 1. Nanometer materials exhibit a oft larger open theater of operations for a certain mass or volume compared to conventional particles 2. The oxide nanoparticles are the materials with good electrical, optical, magnetic, and catalytic properties that are different from their bulk counterparts 3. Reduction in the particle size of it lessens the transient heat conduction travel through with(predicate) the particle over time, and an increase in the spring up-to-volume ratio leads to better dispersal of the particles in the mixture, increasing the reactant sites. Finally, the nanometer particles understructure have completely different surface chemistry, often better than their micron-sized counterparts 4. Among these nanostructure oxides, titanium dioxide or titania (TiO2) nanostructures have emerged as one of the most promising materials because of their potential for gas sensors, especially for humidity and oxygen detection 2, 3, 5, optical devices 3, 5, 6, photocatalysis 2, 3, 6, fabricating capacitors in microelectronic devices due(p) to its unusually high dielectric constant 3, 6, pigments 2, 7, adsorbents 7, and solar cells 5. A relati vely low level of TiO2 is needed to achieve a white black coating which is resistant to discoloration under ultraviolet light. TiO2 pigment is utilize in many diverse products, such as paints, coatings, glazes, enamels, plastics, papers, inks, fibers, foods, pharmaceuticals or cosmetics. clear titanium dioxide is colorless in the massive relegate, non-toxic, thermally stable, inert versus acids, alkalis and solvents, and insoluble. It exists under three fundamental crystalline material bodys rutile which is the most stable and the most great form, anatase (octahedrite) and brookite. All three forms occur naturally but the latter is rather rare and has no commercial interest. Anatase becomes more stable than rutile when the particle size is decreased below 14 nm. Generally s decimal pointing, the functional properties of nano-TiO2 are influenced by a large number of factors such as particle size, surface field of force, synthesis manner and conditions, and crystallinity 2.The presence of nano metals and metal oxides especially transition metal oxides as the nanocatalyst in square propellant formulations tailors the thermal decomposition of ammonium perchlorate (AP in short). Thermal decomposition improvement of AP as a potent oxidizer salt has attracted many attentions 1, 4, 8-10. Decrease amounts of decomposition temperature of AP in the presence of the different nano metal and metal oxides are summarized in remand 1. slacken 1 is hereVargeese 26 showed that signifi standt step-down in activation expertness indicates a strong catalytic natural action of TiO2 on the thermal decomposition of AP. Fujimura and Miyake 27 studied the effect of specific surface area of TiO2 on the thermal decomposition of AP and concluded that the thermal decomposition temperature of AP decreases when the specific surface area of TiO2 increases.The catalytic effect of commercial nanometer titanium dioxide on the thermal decomposition of AP is investigated within the sco pe of this study.2. Materials and method actings2.1. MaterialsAmmonium perchlorate (monomodal 120 m) was purchased from Merck. Commercial nano-TiO2 in anatase form was purchased from Pishgaman Company located in Mashhad, Iran ( forecast. 1). Its purity was more than 99%. Chemical composition and physical properties of nano-TiO2 are given in Tables 2 and 3, respectively.Table 2 is hereTable 3 is here2.2. Methods2.2.1. roentgenogram diffraction analysisX-ray diffraction (XRD) patterns of TiO2 nanoparticles was performed with a Philips PW 1800 powder X-ray diffractometer using CuK radiation therapy at 40 kV and 30 mA.2.2.2. transmittal Electron MicroscopyTransmission electron microscopy (TEM) image of nano-TiO2 was prepared on a Philips transmission electron microscope operated at an accelerating voltage of 100 kV.2.2.3. Thermogravimetry analysisThe thermal decomposition processes of the samples were characterized by thermogravimetry analysis (TGA) using Dupont cc0 instrument at a h eating rate of 10 C/min until temperature of 600 C.2.2.4. Sample preparationThe AP was mixed with various mass loadings of TiO2 nanoparticles namely 1, 2, and 3 wt.% to prepare the samples for thermal decomposition study. Theses samples were tagged as AP1T (AP+1% nano-TiO2), AP2T (AP+2% nano-TiO2), and AP3T (AP+3% nano-TiO2). Before thermal decomposition experiments using TGA technique, the samples were homogenized.3. Results and discussion3.1. Characterization of nanostructureThe TEM analysis was performed to confirm the actual size of the particles and the distribution of the crystallites. It is clear from the micrograph that the average size of the particles is located in bleed of 10-25 nm. TEM image of TiO2 nanoparticles is shown in escort 2. Clear spherical structure shag be seen from this figure. Figure 3 shows the X-ray diffractogram of the commercial nano-TiO2. It mickle be obviously seen that that diffraction peaks appear in the pattern associated with the anatase phas e with proper crystalline nature. A very strong anatase peak is observed at 2 of 25.25, assigned to (101) plane. Other anatase peaks are observed at 2 of 37.7 (004), 47.7 (200), 53.54 (105), and 62.32 (204).3.2. Catalytic activity of nano-titaniaFigure 4 shows the TGA curve for the thermal decomposition of concentrated AP. As can be seen in figure 4, the first exothermic peak is appeared in temperature of 327 C that attended by a saddle loss of 18 wt.%. This peak can be related to the fond(p) decomposition of AP and the formation of some NH3 and HClO4 via dissociation and sublimation. The second exothermic peak is occurred in temperature of 411 C. The weight loss in this stage is about 92 wt.% that is corresponding to complete decomposition of transition products to volatile products. Figure 5 presents the TGA curves associated with thermal decomposition of AP in the presence of 1, 2, and 3 wt.% of TiO2 nanoparticles. From this figure, it is clear that the partial derivative de composition of AP in the presence of 1, 2, and 3 wt.% of TiO2 nanoparticles is happened in a temperature much lower than 327 C. Also, complete decomposition of AP in the presence of 1, 2, and 3 wt.% of TiO2 nanoparticles is occurred in temperatures of 370, 360, and 350 C, respectively that accompanied by decrease of 41, 51, and 61C, respectively. It is obvious that supplement of nano-sized TiO2 to AP has deep effect on the exothermic decomposition of AP. According to these results, it can be concluded that the catalytic effect of nano-sized TiO2 is observed mainly on high-temperature decomposition process and not on the initial stages of decomposition.3.3. Mechanism of thermal decomposition of AP Based on the recent studies, devil main mechanisms have been suggested for thermal decomposition of AP 11, 16, 17, 21First mechanism electron transfer from perchlorate ion to ammonium ion which is as followsClO4+NH3+ClO40+NH40NH40NH3+HClO40+ClO4=ClO4+ClO40HClO4+H urine+ClO3Second mechanis m proton transfer from ammonium ion to perchlorate ion which is as followsNH4ClO4(s) NH4++ClO4NH3(s) +HClO4(s) NH3(g) +HClO4(g)For first mechanism, it is proposed that the rate-determining stage is electron transfer and inasmuch as the p-type semiconductors have positive holes, they can accept the released electron from perchlorate ion. Thus, these catalysts accelerate the electron transfer.eoxide+ClO4Ooxide+ClO31/2O2+ClO3+eoxidein which eoxide is a positive hole in the valence band of the oxide and Ooxide is an abstracted oxygen atom from oxide. It is clear that this mechanism includes two steps 1) oxidation of ammonia and 2) dissociation of ClO4 species into ClO3 and O2.In first step, metal oxides exhibit high catalytic activity in ammonia oxidation and in second step metal oxides accept the released electron from ammonia oxidation that may promote the dissociation of ClO4 into ClO3 and O2.For second mechanism, steps (I)-(III) have been proposed. In step (I), the ammonium and p erchlorate ions are paired. Step (II) is started with proton transfer from NH4+ cation to ClO4 anion and the molecular complex is formed that then is decomposed into NH3 and HClO4 in step (III). The molecules of NH3 and HClO4 react in adsorbed layer on the perchlorate surface or they are desorbed and sublimed that is accompanied by interactions in gas phase.NH4+ClO4 NH3-H-ClO4 NH3-HClO4 NH3(a)+HClO4(a)(I) (II) (III) NH3(g)+HClO4(g)At low temperature (2, N2O, Cl2, NO, and H2O are formed.Based on proton transfer, during high-temperature decomposition, the nanoparticles adsorb the reactive molecules on their surface and catalyse the reaction. The existence of more holes in p-type semiconductor catalysts is responsible for the increasing of the AP decomposition.In this study, the mechanism of thermal decomposition of AP in the presence of the TiO2 nanoparticles can be explained as followsTitanium has the electronic configuration of Ar3d24s2. Experiments have demonstrated that it ca n form both +3 and +4 oxidation state, so it can lose 3 or 4 electrons to form cations. The +4 state is the most common and stable, because it is able to form an octet. The +3 state is less stable (more reactive) because it leaves a single d electron in the valence orbital.Ti4+ cation in TiO2 structure has s and d-type orbitals with 3d04s0 electronic configuration. These orbitals have not been modify with electrons and provide a useful space for electron transfer in AP thermal decomposition and play the role of a bridge. By judge transferred electrons resulted from ClO4 humiliation, ClO4 degradation is promoted. On the other hand, TiO2 nanoparticles have high specific surface area and large amount of surface active sites that increase adsorption of reactive molecules in gas phase to the surface and promote the redox reactions between them.4. ConclusionsThe results of thermogravimetry analysis show that the nanometer titanium dioxide has significant catalytic effect on the therma l decomposition of ammonium perchlorate. The presence of nano-sized titanium dioxide improves significantly the thermal decomposition of ammonium perchlorate. With increase of content of nanometer titanium dioxide, the decrease in decomposition temperature of ammonium perchlorate becomes greater.References1 Jennifer, LS, Matthew, AS, Sameer, D, Eric, LP, and Sudipta, S seize with teeth rate sensitization of solid propellants using a nano-titania additive. In minutes of the 20th international colloquium on the dynamics of explosions and reactive systems, McGill University, Montreal, Canada, July 31-August 5 2005.2 Marie-Isabelle, B Nano-TiO2 for solar cells and photocatalytic water splitting scientific and technological challenges for commercialization. The Open Nanoscience journal, 5, 64-77 (2013).3 Suresh, S subtraction and electrical properties of TiO2 nanoparticles using a wet chemical technique. American Journal of Nanoscience and Nanotechnology, 1(1), 27-30 (2013).4 Demko, A R, Johnson, M, Allen, TW, Reid, DL, and Seal, S Comparison of commercially available and synthesized titania nano-additives on the burning rate of involved HTPB/AP propellant samples. Spring technical coming upon of the central states section of the combustion institute, April 22-24 2012.5 MortezaAli, A, and Saeideh, RS Study of growth parameters on geomorphological properties of TiO2 nanowires. Journal of Nanostructure in chemical science, 3, 35 (2013).6 Karimi, L and Zohoori, S Superior photocatalytic degradation of azo dyes in aqueous solutions using TiO2/SrTiO3 nanocomposite. Journal of Nanostructure in Chemistry, 3, 32 (2013).7 Vijayalakshmi, R and Rajendran, V Synthesis and characterization of nano-TiO2 via different methods. Archives of apply Science Research, 4(2), 1183-1190 (2012).8 Goncalves, RFB, Rocco, AFF and Iha, K Thermal decomposition kinetics of aged solid propellants based on ammonium perchlorate-AP/HTPB binder. INTECH, doi 10.5772/52109.9 Rodic, V Effect of t itanium (IV) oxide on composite solid propellant properties. Scientific Technical Review, 62(3-4), 21-27 (2012).10 Matthew, AS, Eric, LP, Carro, R, David, LR and Sudipta, S Multi-parameters study of nanoscale TiO2 and CeO2 additives in composite AP/HTPB solid propellants. Propellants, Explosives, Pyrotechnics, 35(2), 143-152 (2010).11 Chen, W, Li, F, Liu, L and Li, Y Synthesis of nano-yttria via a sol-gel process based on hydrated yttrium treat and ethylene glycol and its catalytic procedure for thermal decomposition of NH4ClO4. Journal of Rare Earths, 24, 543-548 (2006).12 Zhenye, MA, Fengsheng, L and Aisi, C training and thermal decomposition mien of TMOs/AP composite nanoparticles. Nanoscience, 11(2), 142-145 (2006).13 Yanping, W, Junwu, Z, Xujie, Y, Lude, L and Xin, W Preparation of NiO nanoparticles and their catalytic activity in the thermal decomposition of ammonium perchlorate. Thermochimica Acta, 437, 106-109 (2005).14 Hungzhen, D, Xiangyang, L, Guanpeng, L, Lei, X and Fengsheng, L Synthesis of Ni nanoparticles and their catalytic effect on the decomposition of ammonium perchlorate. Materials processing technology, 208, 494-498 (2008).15 Guorong, D, Xujie, Y, Jian, C, Guohong, H, Lude, L and Xin, W The catalytic effect of nanosized MgO On the decomposition of ammonium perchlorate. powderise Technology, 172, 27-29 (2007).16 Satyawati, SJ, Prajakta, RP and Krishnamurthy, VN Thermal decomposition of ammonium perchlorate in the presence of nanosized ferric oxide. falsifying Science Journal, 58(6), 721-727 (2008).17 Shusen, Z and Dongxu, M Preparation of CoFe2O4 nanocrystallites by solvothermal process and its catalytic activity on the thermal decomposition of ammonium perchlorate. Hindawi Publishing great deal Journal of Nanomaterials, (2010). doi10.1155/2010/842816.18 Han, A, Liao, J, Ye, M, Li, Y and Peng, X Preparation of Nano-MnFe2O4 and its catalytic performance of thermal decomposition of Ammonium perchlorate. Chinese Journal of Chemical Engi neering, 19, 1047-1051 (2011).19 Yifu, Z, Xinghai, L, Jiaorong, N, Lei, Y, Yalan, Z and Chi, H Improve the catalytic activity of -Fe2O3 particles in decomposition of ammonium perchlorate by coating amorphous carbon on their surface. Journal of straightforward State Chemistry, 184, 387-390 (2011).20 Yu, Z, Chen, L, Lu, L, Yang, X and Wang, X DSC/TG-MS study on in situ catalytic thermal decomposition of ammonium perchlorate over CoC2O4. Chinese Journal of Catalysis, 30(1), 19-23 (2009).21 Alizadeh-Gheshlaghi, E, Shaabani, B, Khodayari, A, Azizian-Kalandaragh, Y and Rahimi, R Investigation of the catalytic activity of nano-sized CuO, Co3O4 and CuCo2O4 powders on thermal decomposition of ammonium perchlorate. Powder Technology, 217, 330-339 (2012).22 Wang, J, He, S, Li, Z, Jing, X, Zhang, M and Jiang, Z Synthesis of chrysalis-like CuO nano-crystals and their catalytic activity in the thermal decomposition of ammonium perchlorate. J. Chem. Sci., 121, 1077-1081 (2009).23 Liu, T, Wang, L, Yang, P and Hu, B Preparation of Nanometer CuFe2O4 by auto-combustion and its catalytic activity on the thermal decomposition of ammonium perchlorate. Materials Letters, 62, 4056-4058 (2008).24 Duan, H, Lin, X, Liu, G and Xu, L Synthesis of Co nanoparticles and their catalytic effect on the decomposition of ammonium perchlorate, Chinese Journal of Chemical Engineering, 16, 325-328 (2008).25 Pratibha, S, Reena, D, Kapoor, IPS and Singh, G Synthesis, characterization and catalytic effect of bimetallic nanocrystals on the thermal decomposition of ammonium perchlorate. Indian Journal of Chemistry, 49A, 1339-1344 (2010).26 Vargeese, A Effect of anatase-brookite mixed phase titanium dioxide nanoparticles on the high temperature decomposition kinetics of ammonium perchlorate. Materials Chemistry and Physics, 139(2-3), 537-542 (2013).27 Fujimura, K and Miyake, A The effect of specific surface area of TiO2 on the thermal decomposition of ammonium perchlorate. J Therm Anal Calorim, 99, 27-31 (2010).Figure legendsFigure 1. Commercial nano-TiO2 used in this studyFigure 2. TEM image of TiO2 nanoparticlesFigure 3. XRD patterns of TiO2 nanoparticlesFigure 4. TGA curve related to pure APFigure 5. TGA curves related to (a) AP1T, (b) AP2T, and (c) AP3TTable 1. Reported data from the literature on the decrease in AP decomposition temperature in the presence of different nano metal and metal oxides.NanocatalystPreparation methodAmount (wt.%)Decrease in decomposition temperature (C)ReferenceNano-yttriaSol-gel5114.611CuO/AP composite nanoparticlesA novel solvent-nonsolvent method95.8312Co2O3/AP composite nanoparticlesA novel solvent-nonsolvent method137.1112NiO nanoparticlesSolid-state reaction29313Ni nanoparticlesHydrogen plasma method2-592-10514Nano-sized MgOSol-gel27515Nano-sized -Fe2O3Electrochemical method25916Nanometer CoFe2O4Polyol-medium solvothermal2112.817Nano-MnFe2O4Co-precipitation phase inversion377.318Nano-MnFe2O4Low-temperature combustion384.918Sphere-like -Fe2O3NH 3H2O and NaOH solution to adjust the pH value8119pod-like -Fe2O3NH3H2O and NaOH solution to adjust the pH value7219Nanometer CoC2O4Co-precipitation210420Nano-sized CuOSol-gel90.4721Nano-sized Co3O4Sol-gel92.0721Nano-sized CuCo2O4Sol-gel102.7821CuO nanocrystalsSimple chemical deposition28522Nanometer CuFe2O4Auto-combustion method210523Co nanoparticlesHydrogen plasma2145.0124Cu-Co nanocrystalHydrazine reduction in ethylene glycol19625Cu-Fe189Cu-Zn1114Table 2. Chemical composition of nano-TiO2ElementMgNbAlSSiCaAmount (ppm)Table 3. physiological properties of nano-TiO2Bulk density (g/cm3)Actual density (g/cm3)Average particle size (nm)Specific surface area (m2/g)Color0.243.9010 to 25200 to 240white1