Pub Date : 2019-01-17DOI: 10.5772/INTECHOPEN.83003
T. Shabatina
This chapter reviews the methods of supramolecular chemistry and cryochemistry to study the formation, morphological and structural properties, and possible applications of hybrid nanostructures and nanosized aggregates comprising plasmonic metals (silver and copper) and several mesogenic compounds, which exhibit different liquid crystalline mesophases — nematics, smectics, and cholesterics. Low-temperature vacuum co-condensation of reagent vapors on cooled surfaces of quartz, KBr, CaF 2 , or polished copper was used to synthesize hybrid nanosystems including silver and copper and long-chain mesogenic derivatives of alkylcyanobiphenyls under molecular beam condi- tions. Controlled thermal treatment of the samples allowed the directed formation of metal nanoparticles of definite size from 2 up to 100 nm. It was shown that the procedures of temperature treatments and molecular self-organization of different liquid crystalline phases controlled the size and morphology of nanoparticles and their aggregates, which were formed in the system. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) data of the samples show the formation of orientationally ordered structures in nematic mesophases. Formation of flat 2D aggregates was found in layered smectic mesophases. Optical absorbance spectra of silver/4-pentyl-4-cyanobiphenyl (Ag/ 5 СВ ) and copper/4-pentyl-4-cyanobiphenyl (Cu/5CB) samples encapsulated in polymer poly-para-xylylene at 300 K contained characteristic bands of plasmonic absorbance of metal nanoparticles at 420 – 440 nm and 560 – 600 nm. Rising metal concentration in the sample led to the performable growth of rod-like metal particles with anisometric ratio l/d > 20 and intensive absorbance at higher wavelengths ( λ ≥ 650 nm). New hybrid nanosystems based on biomolecules of cholesterol or its heteroatomic analog thiocholesterol including nanosized silver particles of d = 5.0 (cid:1) 0.5 and d = 2.5 (cid:1) 0.5 nm, respectively, were obtained. Highly ordered 1D-, 2D-, and 3D structures containing silver nanoparticles were formed from concentrated organic sols at different support surfaces by removing the inert solvent from triple metal/ligand/solvent system and by cooling the binary metal/ligand system from isotropic state to the cholesteric liquid crystalline mesophase. The microstructure and composition of the hybrid nanosystems were characterized by FTIR, UV-Vis spectro- scopy, TEM, and selected area electron diffraction (SAED). It was shown that hybrid nanosystems based on silver nanoparticles covered by a stabilizing layer of mesogenic molecules of thiocholesterol display selectivity in adsorption of optical isomers of the selected compounds. definite morphology with biological molecules and blocks opens new perspectives for obtaining new bio-compatible instruments for imaging and sensing biological objects in living organisms and targeted medical therapy. The hybrid metal-mesogenic nanosystems obtained were also used
{"title":"Self-Assembled Nanostructures Formation in Hybrid Metal-Mesogenic Systems","authors":"T. Shabatina","doi":"10.5772/INTECHOPEN.83003","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.83003","url":null,"abstract":"This chapter reviews the methods of supramolecular chemistry and cryochemistry to study the formation, morphological and structural properties, and possible applications of hybrid nanostructures and nanosized aggregates comprising plasmonic metals (silver and copper) and several mesogenic compounds, which exhibit different liquid crystalline mesophases — nematics, smectics, and cholesterics. Low-temperature vacuum co-condensation of reagent vapors on cooled surfaces of quartz, KBr, CaF 2 , or polished copper was used to synthesize hybrid nanosystems including silver and copper and long-chain mesogenic derivatives of alkylcyanobiphenyls under molecular beam condi- tions. Controlled thermal treatment of the samples allowed the directed formation of metal nanoparticles of definite size from 2 up to 100 nm. It was shown that the procedures of temperature treatments and molecular self-organization of different liquid crystalline phases controlled the size and morphology of nanoparticles and their aggregates, which were formed in the system. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) data of the samples show the formation of orientationally ordered structures in nematic mesophases. Formation of flat 2D aggregates was found in layered smectic mesophases. Optical absorbance spectra of silver/4-pentyl-4-cyanobiphenyl (Ag/ 5 СВ ) and copper/4-pentyl-4-cyanobiphenyl (Cu/5CB) samples encapsulated in polymer poly-para-xylylene at 300 K contained characteristic bands of plasmonic absorbance of metal nanoparticles at 420 – 440 nm and 560 – 600 nm. Rising metal concentration in the sample led to the performable growth of rod-like metal particles with anisometric ratio l/d > 20 and intensive absorbance at higher wavelengths ( λ ≥ 650 nm). New hybrid nanosystems based on biomolecules of cholesterol or its heteroatomic analog thiocholesterol including nanosized silver particles of d = 5.0 (cid:1) 0.5 and d = 2.5 (cid:1) 0.5 nm, respectively, were obtained. Highly ordered 1D-, 2D-, and 3D structures containing silver nanoparticles were formed from concentrated organic sols at different support surfaces by removing the inert solvent from triple metal/ligand/solvent system and by cooling the binary metal/ligand system from isotropic state to the cholesteric liquid crystalline mesophase. The microstructure and composition of the hybrid nanosystems were characterized by FTIR, UV-Vis spectro- scopy, TEM, and selected area electron diffraction (SAED). It was shown that hybrid nanosystems based on silver nanoparticles covered by a stabilizing layer of mesogenic molecules of thiocholesterol display selectivity in adsorption of optical isomers of the selected compounds. definite morphology with biological molecules and blocks opens new perspectives for obtaining new bio-compatible instruments for imaging and sensing biological objects in living organisms and targeted medical therapy. The hybrid metal-mesogenic nanosystems obtained were also used","PeriodicalId":178525,"journal":{"name":"Nanostructures in Energy Generation, Transmission and Storage","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128889022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-05DOI: 10.5772/INTECHOPEN.80729
Y. Fedorenko
{"title":"Introductory Chapter: Electron Microscopy - Research Highlights","authors":"Y. Fedorenko","doi":"10.5772/INTECHOPEN.80729","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.80729","url":null,"abstract":"","PeriodicalId":178525,"journal":{"name":"Nanostructures in Energy Generation, Transmission and Storage","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127108561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-05DOI: 10.5772/INTECHOPEN.78339
R. Maric, Haoran Yu
Proton exchange membrane (PEM) electrolysis is industrially important as a green source of high-purity hydrogen, for chemical applications as well as energy storage. Energy capture as hydrogen via water electrolysis has been gaining tremendous interest in Europe and other parts of the world because of the higher renewable penetration on their energy grid. Hydrogen is an appealing storage medium for excess renewable energy because once stored, it can be used in a variety of applications including power generation in periods of increased demand, supplementation of the natural gas grid for increased efficiency, vehicle fueling, or use as a high-value chemical feedstock for green generation of fertilizer and other chemicals. Today, most of the cost and energy use in PEM electrolyzer manufacturing is contributed by the cell stack manufacturing processes. Current state-of-the-art electrolysis technology involves two options: liquid electrolyte and ion exchange membranes. Membrane-based systems overcome many of the disadvantages of alkaline liquid systems, because the carrier fluid is deionized water, and the membrane-based cell design enables differential pressure operation.
{"title":"Proton Exchange Membrane Water Electrolysis as a Promising Technology for Hydrogen Production and Energy Storage","authors":"R. Maric, Haoran Yu","doi":"10.5772/INTECHOPEN.78339","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.78339","url":null,"abstract":"Proton exchange membrane (PEM) electrolysis is industrially important as a green source of high-purity hydrogen, for chemical applications as well as energy storage. Energy capture as hydrogen via water electrolysis has been gaining tremendous interest in Europe and other parts of the world because of the higher renewable penetration on their energy grid. Hydrogen is an appealing storage medium for excess renewable energy because once stored, it can be used in a variety of applications including power generation in periods of increased demand, supplementation of the natural gas grid for increased efficiency, vehicle fueling, or use as a high-value chemical feedstock for green generation of fertilizer and other chemicals. Today, most of the cost and energy use in PEM electrolyzer manufacturing is contributed by the cell stack manufacturing processes. Current state-of-the-art electrolysis technology involves two options: liquid electrolyte and ion exchange membranes. Membrane-based systems overcome many of the disadvantages of alkaline liquid systems, because the carrier fluid is deionized water, and the membrane-based cell design enables differential pressure operation.","PeriodicalId":178525,"journal":{"name":"Nanostructures in Energy Generation, Transmission and Storage","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132110897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-05DOI: 10.5772/INTECHOPEN.78303
B. Lucas-Granados, R. Sánchez-Tovar, Ramón M. Fernández- Domene, J. García-Antón
Nanostructured semiconductor metal oxides, such as TiO 2 , WO 3 , Fe 2 O 3 or ZnO, are being widely investigated for their use as photoanodes, due to their higher surface areas in contact with the electrolyte, which increases the efficiency of photoelectrochemical processes. Metal oxide nanostructures have been synthesized by a number of different techniques. Anodization is one of the simpler methods used to synthesize nanostructured photoanodes, and the morphology and size of nanostructures can be designed by adequately controlling anodization parameters. Besides, these nanostructures are directly bound to the metallic back contact, improving significantly the efficiency of electron collection. It has been observed that hydrodynamic conditions during anodization (using a rotating disk electrode, RDE) greatly influenced the morphology of nanostructures and, therefore, their photoelectrochemical per -formance. The objective of this chapter is to review the innovative nanostructures with high- aspect ratios that can be fabricated by anodization under different hydrodynamic conditions.
{"title":"Fabrication of Ordered and High-Performance Nanostructured Photoelectrocatalysts by Electrochemical Anodization: Influence of Hydrodynamic Conditions","authors":"B. Lucas-Granados, R. Sánchez-Tovar, Ramón M. Fernández- Domene, J. García-Antón","doi":"10.5772/INTECHOPEN.78303","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.78303","url":null,"abstract":"Nanostructured semiconductor metal oxides, such as TiO 2 , WO 3 , Fe 2 O 3 or ZnO, are being widely investigated for their use as photoanodes, due to their higher surface areas in contact with the electrolyte, which increases the efficiency of photoelectrochemical processes. Metal oxide nanostructures have been synthesized by a number of different techniques. Anodization is one of the simpler methods used to synthesize nanostructured photoanodes, and the morphology and size of nanostructures can be designed by adequately controlling anodization parameters. Besides, these nanostructures are directly bound to the metallic back contact, improving significantly the efficiency of electron collection. It has been observed that hydrodynamic conditions during anodization (using a rotating disk electrode, RDE) greatly influenced the morphology of nanostructures and, therefore, their photoelectrochemical per -formance. The objective of this chapter is to review the innovative nanostructures with high- aspect ratios that can be fabricated by anodization under different hydrodynamic conditions.","PeriodicalId":178525,"journal":{"name":"Nanostructures in Energy Generation, Transmission and Storage","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126101204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-05DOI: 10.5772/INTECHOPEN.78289
L. Manea, A. Bertea
Nanotechnology exerts a significant influence on materials science, providing new insights into the design of functional materials. One of the most studied areas of nano technologies is that of nanofibres, characterised by high specific volume, chemical activ - ity and volume-dependent physical processes. The most promising method of producing nanofibres with various morphologies and functionalities from different materials is electrospinning, where high voltage is applied between the spinneret and the collector to the charged polymer solution (or melt) to draw polymer filaments. This chapter reviews the main electrospinning techniques for producing nanofibres from polymers, provides an overview on the influence of the spinning solution characteristics, the process param - eters and the working environment on the process and highlights the many applications of electrospun nanofibres in the field of sensors. Latest advances in this field and the prospects for obtaining new electrospun nanofibre sensors are discussed.
{"title":"Sensors from Electrospun Nanostructures","authors":"L. Manea, A. Bertea","doi":"10.5772/INTECHOPEN.78289","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.78289","url":null,"abstract":"Nanotechnology exerts a significant influence on materials science, providing new insights into the design of functional materials. One of the most studied areas of nano technologies is that of nanofibres, characterised by high specific volume, chemical activ - ity and volume-dependent physical processes. The most promising method of producing nanofibres with various morphologies and functionalities from different materials is electrospinning, where high voltage is applied between the spinneret and the collector to the charged polymer solution (or melt) to draw polymer filaments. This chapter reviews the main electrospinning techniques for producing nanofibres from polymers, provides an overview on the influence of the spinning solution characteristics, the process param - eters and the working environment on the process and highlights the many applications of electrospun nanofibres in the field of sensors. Latest advances in this field and the prospects for obtaining new electrospun nanofibre sensors are discussed.","PeriodicalId":178525,"journal":{"name":"Nanostructures in Energy Generation, Transmission and Storage","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133173092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-05DOI: 10.5772/INTECHOPEN.79880
T. Takeuchi, Y. Horikoshi
The motivation for developing light-emitting devices on an indirect transition semicon - ductor such as silicon has been widely discussed for Si/SiO 2 nanostructures. In this chapter, we report on the fabrication of Si/SiO 2 quantum-confined amorphous nanostructured films and their optical properties. The Si/SiO 2 nanostructures comprising amorphous Si, SiO 2 , and Si/SiO 2 multilayers are grown using ultrahigh vacuum radio frequency magnetron sputter - ing. Optical absorption coefficients of the Si/SiO 2 nanostructures are evaluated with regard to tentative integrated Si thicknesses. Optical energy band gaps of the Si/SiO 2 multilayer films are in accordance with the effective mass theory and described as E 0 = 1.61 + 0.75d −2 eV at the Si layer-integrated thicknesses ranging from 0.5 to 6 nm. Quantum confinement effects in the Si/SiO 2 nanostructures are inferred from optical transmittance and reflectance spectra. The rapid-thermal-annealed Si/SiO 2 multilayer films demonstrate the intensified photoluminescence at ~1.45 eV due to the formation of nanocrystalline silicon. The tem perature dependence of the nanocrystalline luminescence intensity shows the nonmonoto - nous behavior which is interpreted invoking the Kapoor model.
{"title":"Nanostructured Si/SiO2 Quantum Wells","authors":"T. Takeuchi, Y. Horikoshi","doi":"10.5772/INTECHOPEN.79880","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.79880","url":null,"abstract":"The motivation for developing light-emitting devices on an indirect transition semicon - ductor such as silicon has been widely discussed for Si/SiO 2 nanostructures. In this chapter, we report on the fabrication of Si/SiO 2 quantum-confined amorphous nanostructured films and their optical properties. The Si/SiO 2 nanostructures comprising amorphous Si, SiO 2 , and Si/SiO 2 multilayers are grown using ultrahigh vacuum radio frequency magnetron sputter - ing. Optical absorption coefficients of the Si/SiO 2 nanostructures are evaluated with regard to tentative integrated Si thicknesses. Optical energy band gaps of the Si/SiO 2 multilayer films are in accordance with the effective mass theory and described as E 0 = 1.61 + 0.75d −2 eV at the Si layer-integrated thicknesses ranging from 0.5 to 6 nm. Quantum confinement effects in the Si/SiO 2 nanostructures are inferred from optical transmittance and reflectance spectra. The rapid-thermal-annealed Si/SiO 2 multilayer films demonstrate the intensified photoluminescence at ~1.45 eV due to the formation of nanocrystalline silicon. The tem perature dependence of the nanocrystalline luminescence intensity shows the nonmonoto - nous behavior which is interpreted invoking the Kapoor model.","PeriodicalId":178525,"journal":{"name":"Nanostructures in Energy Generation, Transmission and Storage","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125644406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-05DOI: 10.5772/INTECHOPEN.77727
C. Doroftei
Until recently, for reducing the environment pollution, the combustion catalysts based on noble metals was considered the most active, practically irreplaceable. Their high cost, high thermal instability, high sensitivity to deactivation and to the attack of some harm - ful elements or compounds determine the intensification of studies to replace them with new cheaper and stable catalysts. Numerous experimental data from literature indicate that the semiconductive oxidic compounds can compete with combustion catalysts based on noble metals from catalytic activity standpoint. Recent studies led to the realization of remarkable catalytic activity at moderate (350–600°C) and high (over 600°C) temperatures at some oxidic perovskite compounds, which contain transition metals. In this study are presented a series of nanostructured oxidic compounds with perovskite structure, based on transition metals and synthesized by the precursor method of self-combustion, using polyvinyl alcohol as colloidal medium, for catalytic combustion of some volatile organic compounds at low (50–350°C) and moderate temperatures. The catalytic activity of the perovskite compounds in the total oxidation reactions of the gases is largely determined by the amount of weakly bound surface oxygen species which in turn depends on the presence of oxygen vacancies.
{"title":"Nanostructured Perovskites for Catalytic Combustion","authors":"C. Doroftei","doi":"10.5772/INTECHOPEN.77727","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.77727","url":null,"abstract":"Until recently, for reducing the environment pollution, the combustion catalysts based on noble metals was considered the most active, practically irreplaceable. Their high cost, high thermal instability, high sensitivity to deactivation and to the attack of some harm - ful elements or compounds determine the intensification of studies to replace them with new cheaper and stable catalysts. Numerous experimental data from literature indicate that the semiconductive oxidic compounds can compete with combustion catalysts based on noble metals from catalytic activity standpoint. Recent studies led to the realization of remarkable catalytic activity at moderate (350–600°C) and high (over 600°C) temperatures at some oxidic perovskite compounds, which contain transition metals. In this study are presented a series of nanostructured oxidic compounds with perovskite structure, based on transition metals and synthesized by the precursor method of self-combustion, using polyvinyl alcohol as colloidal medium, for catalytic combustion of some volatile organic compounds at low (50–350°C) and moderate temperatures. The catalytic activity of the perovskite compounds in the total oxidation reactions of the gases is largely determined by the amount of weakly bound surface oxygen species which in turn depends on the presence of oxygen vacancies.","PeriodicalId":178525,"journal":{"name":"Nanostructures in Energy Generation, Transmission and Storage","volume":"168 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132104261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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