Sonochemical methods

The possibility of using sound energy in chemistry was established more than 70 years ago. By definition, sonochemistry is the application of powerful ultrasound radiation (10 kHz to 20 kHz) to cause chemical changes to molecules. The physical phenomenon behind this process is acoustic cavitation. Typical processes that occur in sonochemistry are the creation, growth and collapse of a bubble. A typical laboratory setup for sonochemical reactions is shown in Fig. 8.17. More details of sonochemistry and the theory behind it can be found elsewhere. -  

Titanium Horn CoIlar O-Rings Gas Inlet Oudet 

Sonochemical reaction rates depend on the irradiation frequency, acoustic power and volatility of the solvent, which influence the cavitation strength. From a preparation point of view, sonochemical approaches are advantageous because they speed up reaction rates and favour the formation of porous products with a high specific surface, and have the additional economic benefit of relatively low reaction temperatures. 

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Haas I, Shanmugam S, Gedanken A (2008) Synthesis of copper dendrite nanostructures by a sonochemical method. Chem Eur J 14 4696-7403... 

As described in this chapter, the sonochemical reduction technique appears to be a promising method for the preparation of various types of metal nanoparticles in an aqueous solution. By choosing more efficient organic additives, easily-reducible metal precursors, supports and templates with an appropriate role, more advanced functional nanoparticles could be synthesized successfully using the sonochemical reduction technique. In future, it is also possible to develop effective synthetic methods by combining the sonochemical method with other chemical methods. 

Mizukoshi Y, Fujimoto T, Nagata Y, Oshima R, Maeda Y (2000) Characterization and catalytic activity of core-shell structured gold/palladium bimetallic nanoparticles synthesized by the sonochemical method. J Phys Chem B 104 6028-6032... 

Zhu S, Zhou H, Hibino M, Honma I, Ichihara M (2005) Synthesis of Mn02 nanoparticles confined in ordered mesoporous carbon using a sonochemical method. Adv Funct Mater 15 381-386... 

Basnayake R, Li Z, Katar S, Zhou W, Rivera H, Smotkin ES, Casadonte DJ, Korzeniewski C Jr (2006) PtRu nanoparticle electrocatalyst with bulk alloy properties prepared through a sonochemical method. Langmuir 22 10446-10450... 

Mizukozhi Y, Makise Y, Shuto T, Hu J, Tominaga A, Shrionita S, Tanabe S (2007) Immobilization of noble metal nanoparticles on the surface of Ti02 by the sonochemical method photocatalytic production of hydrogen from an aqueous solution of ethanol. Ultrason Sonochem 14 387-392... 

In addition to the processing technique, the properties of the oxides also changed by preparing them in a composite way. Arefian et al. [18] have synthesized SnO/ ZnO nanocomposite using the sonochemical method and studied the effects of temperature and power on the morphologies generated. Recently Mg doped ZnO... 

Nanostructured anatase with the particle size of 6.2 nm and a specific surface area of 300 m2/g has been produced with the assistance of sonochemical method [35]. 

Preparation of chiral mesoporous materials has become a great interest for material scientists. Normally chiral property is introduced into chiral mesoporous material via an organic chiral templating component. But, by using a sonochemical method, Gabashvili et al. [36] have prepared mesoporous chiral titania using a chiral inorganic precursor and a non-chiral dodecylamine as a template. Size of the pores was 5.5 nm. 

Zirconia nanopowders have attracted much attention recently due to their specific optical and electrical properties [38] and as catalysts [39]. Liang et al. [40] have synthesized pure Zr02 nanopowders via sonochemical method. In this study, the use of ultrasound has dramatically reduced the temperature of reaction and made the reaction conditions very easy to maintain. 

Fig. 8.8 CdS nanoparticles colloid solution prepared by the sonochemical method freshly prepared (a) kept in air for 1 month (b) [63]...

PbS has attracted much attention due to its special direct band gap energy (0.4 eV) and a relatively large exciton Bohr radius (18 nm) and their nanoclusters have potential applications in electroluminescent devices such as light-emitting diodes. PbS nanocrystals with rod like structures with diameters of 20-60 nm and lengths of 1-2 pm have been obtained using the sonochemical method and by using PEG-6000 [66]. Addition of PEG and the time of sonication have been found to play a key role in the formation of these rods. 

An alternative route to obtain NbS2-sheathed carbon nanotubes (CNT) has been proposed by Zhu et al. [71] with this sonochemical method. In this study, CNTs act as templates to produce the uniform and well-crystallized bS2 nanotubes and the formation of such nanotubes has been explained by means of multi-point nuclei site growth mechanism. 

Pejova et al. [72] (2008) have obtained three-dimensional arrays of close-packed semiconducting AgBiS2 quantum dots with an average QD radius of 4.2 nm using sonochemical method which was twice as small as compared to the QD solid obtained without ultrasonic irradiation. 

Karami H, Karimi MA, Haghdar S, Sadeghi A, Mir-Ghasemi R, Mahdi-Khani S (2008) Synthesis of lead oxide nanoparticles by sonochemical method and its application as cathode and anode of lead-acid batteries. Mater Chem Phys 108 337-344... 

Mosadegh Sedghi S, Mortazavi Y, Khodadadi A (2009) Low temperature CO and CH4 dual selective gas sensor using Sn02 quantum dots prepared by sonochemical method. Sens Actu B (In Press)... 

Liang J, Jiang X, Liu G, Deng Z, Zhuang J, Li F, Li Y (2003) Characterisation and synthesis of pure Zr02 nanopowders via sonochemical method. Mater Res Bull 38 161-168... 

Dutta DP, Ghildiyal R, Tyagi AK (2009) Luminescent properties of doped zinc aluminate and zinc gallate white light emitting nanophosphors prepared via sonochemical method. J Phys Chem C 113(39) 16954-16961... 

Syntheses of Mn304 and LiMn204 nanoparticles by a simple sonochemical method. Mater Lett 63 2201-2204... 

Wang H, Zhu JJ, Zhu JM, Chen HY (2002) Sonochemical method for the preparation of bismuth sulfide nanorods. J Phys Chem B 106(15) 3848-3854... 

Zhu Jun-Jie, Wang Hui, Xu Shu, Chen Hong-Yuan Chen (2002) Sonochemical method for the preparation of monodisperse spherical and rectangular lead selenide nanoparticles. Langmuir 18 3306-3310... 

Jeevanandam P, Koltypin Yu, Gedanken A (2006) Synthesis of nanosized a-Nickel hydroxide by sonochemical method. J Mater Sci 41 5598-5601... 

Zho JJ, Yuri K, Gedanken A (2000) General sonochemical method for the preparation of nanophasic selenide synthesis of ZnSe nanoparticles. Chem Mater 12 73-78... 

Neppolian B, Doronila A, Grieser F, Ashokkumar M (2009) Simple and efficient sonochemical method for the oxidation of arsenic (III) to arsenic (V). Environ Sci Technol 43 6793-6798... 

Pradhan A, Jones Robin C, Daniela C, O Connor Charles J, Tarr Matthew A (2008) Gold-magnetite nanocomposite materials formed via sonochemical methods. Ultrason Sonochem 15(5) 891-897... 

Stibnite nanorods Regular stibnite (Sb2S3) nanorods (20-40 nm diameter, 220-350 nm length) have been synthesized by a sonochemical method under ambient air from an ethanolic solution containing SbCl3 and thioacetamide. In about 2 hours the solution self-heated up to about 60°C. The reaction product was separated by centrifuging and washing, in sequence, with absolute ethanol, water, acetone. 

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