P. King, D. Svedružić, Michael S. Hambourger, M. Gervaldo, Timothy D. McDonald, Jeffry L. Blackburn, M. Heben, D. Gust, A. Moore, T. Moore, M. Ghirardi
The catalysts commonly used for the H2 producing reaction in artificial solar systems are typically platinum or particulate platinum composites. Biological catalysts, the hydrogenases, exist in a wide-variety of microbes and are biosynthesized from abundant, non-precious metals. By virtue of a unique catalytic metallo-cluster that is composed of iron and sulfur, [FeFe]-hydrogenases are capable of catalyzing H2 production at turnover rates of millimoles-per-second. In addition, these biological catalysts possess some of the characteristics that are desired for cost-effective solar H2 production systems, high solubilities in aqueous solutions and low activation energies, but are sensitive to CO and O2. We are investigating ways to merge [FeFe]-hydrogenases with a variety of organic materials and nanomaterials for the fabrication of electrodes and biohybrids as catalysts for use in artificial solar H2 production systems. These efforts include designs that allow for the integration of [FeFe]-hydrogenase in dye-solar cells as models to measure solar conversion and H2 production efficiencies. In support of a more fundamental understanding of [FeFe]-hydrogenase for these and other applications the role of protein structure in catalysis is being investigated. Currently there is little known about the mechanism of how these and other enzymes couple multi-electron transfer to proton reduction. To further the mechanistic understanding of [FeFe]-hydrogenases, structural models for substrate transfer are being used to create enzyme variants for biochemical analysis. Here results are presented on investigations of proton-transfer pathways in [FeFe]-hydrogenase and their interaction with single-walled carbon nanotubes.
{"title":"Merging [FeFe]-hydrogenases with materials and nanomaterials as biohybrid catalysts for solar H2 production","authors":"P. King, D. Svedružić, Michael S. Hambourger, M. Gervaldo, Timothy D. McDonald, Jeffry L. Blackburn, M. Heben, D. Gust, A. Moore, T. Moore, M. Ghirardi","doi":"10.1117/12.736556","DOIUrl":"https://doi.org/10.1117/12.736556","url":null,"abstract":"The catalysts commonly used for the H2 producing reaction in artificial solar systems are typically platinum or particulate platinum composites. Biological catalysts, the hydrogenases, exist in a wide-variety of microbes and are biosynthesized from abundant, non-precious metals. By virtue of a unique catalytic metallo-cluster that is composed of iron and sulfur, [FeFe]-hydrogenases are capable of catalyzing H2 production at turnover rates of millimoles-per-second. In addition, these biological catalysts possess some of the characteristics that are desired for cost-effective solar H2 production systems, high solubilities in aqueous solutions and low activation energies, but are sensitive to CO and O2. We are investigating ways to merge [FeFe]-hydrogenases with a variety of organic materials and nanomaterials for the fabrication of electrodes and biohybrids as catalysts for use in artificial solar H2 production systems. These efforts include designs that allow for the integration of [FeFe]-hydrogenase in dye-solar cells as models to measure solar conversion and H2 production efficiencies. In support of a more fundamental understanding of [FeFe]-hydrogenase for these and other applications the role of protein structure in catalysis is being investigated. Currently there is little known about the mechanism of how these and other enzymes couple multi-electron transfer to proton reduction. To further the mechanistic understanding of [FeFe]-hydrogenases, structural models for substrate transfer are being used to create enzyme variants for biochemical analysis. Here results are presented on investigations of proton-transfer pathways in [FeFe]-hydrogenase and their interaction with single-walled carbon nanotubes.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121711028","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}
R. Hesse, R. Caballero, D. Abou‐Ras, T. Unold, C. Kaufmann, H. Schock
A new method for optical process control of the three-stage co-evaporation of Cu(In,Ga)Se2 thin films is presented. Precise control of the deposition process is desirable as the field of process parameters is rather complex. In an enhancement to laser light scattering (LLS) with a single photo-detector, the diffuse part of the scattered laser light is now used to a larger extent. In consequence, it is possible to deduce compositional information (e.g., the Ga/III-ratio) for the deposited layer with high accuracy. This is demonstrated in a series of experiments on Mo-coated float glass and titanium foil substrates where the final Ga content of the Cu(In,Ga)Se2 thin film has been intentionally varied. As an additional benefit of the enhanced LLS system, the new system can also be used for process control, in cases where previously the intensity of scattered component of light has not been sufficient for reliable interpretation. The information from this new monitoring technique was used to set up an optical model for semitransparent, coevaporated InxGaySez-layers of various compositions. Using this model, an evaluation of phases formed during the process and adjustment of deposition parameters is possible. The knowledge of phases formed on glass and titanium substrates is important since the Cu(In,Ga)Se2 formation depends on properties of the InxGaySez-layer evaporated in stage 1 of the three-stage process. Break-off experiments at different points within stage 1 were carried out to test and improve the model. Depth profiling by means of x-ray fluorescence (XRF) and microstructural studies by means of x-ray diffraction (XRD) also deliver valuable information for the optical model.
提出了一种控制Cu(In,Ga)Se2薄膜三段共蒸发光学过程的新方法。由于工艺参数领域相当复杂，需要对沉积过程进行精确控制。在单光电探测器增强激光光散射(LLS)中，散射激光的漫射部分被更大程度地利用。因此，可以高精度地推断沉积层的成分信息(例如Ga/ iii -比值)。这在mo涂层浮法玻璃和钛箔衬底上的一系列实验中得到了证明，其中Cu(in,Ga)Se2薄膜的最终Ga含量被有意地改变。作为增强型LLS系统的另一个好处，新系统还可以用于过程控制，在以前光散射成分的强度不足以进行可靠解释的情况下。从这种新的监测技术的信息被用来建立一个光学模型的半透明，共蒸发inxgaysez层的各种成分。利用该模型，可以对沉积过程中形成的相进行评估，并对沉积参数进行调整。了解在玻璃和钛基板上形成的相是很重要的，因为Cu(In,Ga)Se2的形成取决于在三阶段工艺的第一阶段蒸发的inxgaysez层的性质。在第一阶段的不同时间点进行断裂实验，对模型进行检验和改进。x射线荧光(XRF)的深度剖面和x射线衍射(XRD)的微观结构研究也为光学模型提供了有价值的信息。
{"title":"A reliable optical method for in situ process control for deposition of Cu(In,Ga)Se2 thin layers for photovoltaics","authors":"R. Hesse, R. Caballero, D. Abou‐Ras, T. Unold, C. Kaufmann, H. Schock","doi":"10.1117/12.733726","DOIUrl":"https://doi.org/10.1117/12.733726","url":null,"abstract":"A new method for optical process control of the three-stage co-evaporation of Cu(In,Ga)Se2 thin films is presented. Precise control of the deposition process is desirable as the field of process parameters is rather complex. In an enhancement to laser light scattering (LLS) with a single photo-detector, the diffuse part of the scattered laser light is now used to a larger extent. In consequence, it is possible to deduce compositional information (e.g., the Ga/III-ratio) for the deposited layer with high accuracy. This is demonstrated in a series of experiments on Mo-coated float glass and titanium foil substrates where the final Ga content of the Cu(In,Ga)Se2 thin film has been intentionally varied. As an additional benefit of the enhanced LLS system, the new system can also be used for process control, in cases where previously the intensity of scattered component of light has not been sufficient for reliable interpretation. The information from this new monitoring technique was used to set up an optical model for semitransparent, coevaporated InxGaySez-layers of various compositions. Using this model, an evaluation of phases formed during the process and adjustment of deposition parameters is possible. The knowledge of phases formed on glass and titanium substrates is important since the Cu(In,Ga)Se2 formation depends on properties of the InxGaySez-layer evaporated in stage 1 of the three-stage process. Break-off experiments at different points within stage 1 were carried out to test and improve the model. Depth profiling by means of x-ray fluorescence (XRF) and microstructural studies by means of x-ray diffraction (XRD) also deliver valuable information for the optical model.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114187921","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}
A Quantum Dot Solar Concentrator (QDSC) is based on the Luminescent Solar Concentrator (LSC), a concept first introduced in the 1960s. LSCs consist of a flat plate of polymer material doped with a luminescent dye. A percentage of incident insolation, absorbed and re-emitted by the dye molecules is trapped inside the plate by total internal reflection. Reflective material situated on three of the edges and the back surface increases the trapping efficiency of the plate. Through successive reflection events light is concentrated onto a photovoltaic (PV) cell positioned on the fourth edge of the plate. Degradation of luminescent dyes prevented LSCs from being fully developed. A QDSC replaces luminescent dyes with semiconductor nanocrystals known as quantum dots (QDs). Passivation of QD cores with shells of higher band gap material is expected to provide increased stability. QDs offer further advantages such as broad absorption spectra to utilize more of the solar spectrum and size tunability that allows spectral matching of the QDs emission to the peak efficiency of PV cells. Small-scale QDSCs have been fabricated using QDs bought commercially. The QDs have an emission wavelength of 600nm, close to the peak efficiency of a typical silicon PV cell. The systems were electrically characterized using a 4 cm monocrystalline PV cell optically matched to the QDSC edge with silicon oil. To investigate the effect of shape and size on concentrator efficiency, four different sized quadratic, two triangular and three circular QDSCs of various diameters were fabricated.
{"title":"Quantum dot solar concentrators: an investigation of various geometries","authors":"B. Rowan, S. McCormack, J. Doran, Brian Norton","doi":"10.1117/12.733572","DOIUrl":"https://doi.org/10.1117/12.733572","url":null,"abstract":"A Quantum Dot Solar Concentrator (QDSC) is based on the Luminescent Solar Concentrator (LSC), a concept first introduced in the 1960s. LSCs consist of a flat plate of polymer material doped with a luminescent dye. A percentage of incident insolation, absorbed and re-emitted by the dye molecules is trapped inside the plate by total internal reflection. Reflective material situated on three of the edges and the back surface increases the trapping efficiency of the plate. Through successive reflection events light is concentrated onto a photovoltaic (PV) cell positioned on the fourth edge of the plate. Degradation of luminescent dyes prevented LSCs from being fully developed. A QDSC replaces luminescent dyes with semiconductor nanocrystals known as quantum dots (QDs). Passivation of QD cores with shells of higher band gap material is expected to provide increased stability. QDs offer further advantages such as broad absorption spectra to utilize more of the solar spectrum and size tunability that allows spectral matching of the QDs emission to the peak efficiency of PV cells. Small-scale QDSCs have been fabricated using QDs bought commercially. The QDs have an emission wavelength of 600nm, close to the peak efficiency of a typical silicon PV cell. The systems were electrically characterized using a 4 cm monocrystalline PV cell optically matched to the QDSC edge with silicon oil. To investigate the effect of shape and size on concentrator efficiency, four different sized quadratic, two triangular and three circular QDSCs of various diameters were fabricated.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"12 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124095417","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}
Two types of solar concentrators for use with standard silicon photovoltaic cells are compared. The first is a spectral shifting luminescent concentrator that absorbs light in one spectral band and re-emits light at longer wavelengths where the absorption of standard silicon photovoltaic cells is more efficient. The second type is a holographic planar concentrator that selects the most useful bands of the solar spectrum and concentrates them onto the surface of the photovoltaic cell. Both types of concentrators take advantage of total internal reflected light, do not require tracking, and can operate with both direct and diffuse sunlight. The holographic planar concentrator provides a simpler and more cost effective solution with existing materials and construction methods.
{"title":"Spectral-shifting and holographic planar concentrators for use with photovoltaic solar cells","authors":"R. Kostuk, J. Castillo, J. Russo, Glenn Rosenberg","doi":"10.1117/12.736542","DOIUrl":"https://doi.org/10.1117/12.736542","url":null,"abstract":"Two types of solar concentrators for use with standard silicon photovoltaic cells are compared. The first is a spectral shifting luminescent concentrator that absorbs light in one spectral band and re-emits light at longer wavelengths where the absorption of standard silicon photovoltaic cells is more efficient. The second type is a holographic planar concentrator that selects the most useful bands of the solar spectrum and concentrates them onto the surface of the photovoltaic cell. Both types of concentrators take advantage of total internal reflected light, do not require tracking, and can operate with both direct and diffuse sunlight. The holographic planar concentrator provides a simpler and more cost effective solution with existing materials and construction methods.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"132 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114471853","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}
Common methods for ground-based measurement of direct normal and diffuse solar irradiance include the simultaneous use of two instruments, usually a pyrheliometer and pyranometer or two pyranometers one of which is fitted with a shading ring. This article describes a passive method of obtaining the direct and diffuse components using a single pyranometer and an innovative shading band containing regularly spaced perforations to allow for alternate shading and exposure of the instrument's sensor as the sun transits the sky. Under clear sky conditions a saw tooth curve is generated that may be reformed into two distinct curves, one each for global and diffuse irradiance. The unknown direct normal values are then readily calculated. The approach potentially offers a cost advantage over dual-instrument and rotating band systems and an accuracy advantage over the single-instrument approach. In conjunction with a reference pyrheliometer under clear sky conditions, the device can be used in shade-unshade calibrations of pyranometers without need of manual operations. Design of the shading band is described and preliminary experimental results are presented. Results show that good accuracy is obtainable, on the order of ± 40 Watts per square meter for global, diffuse and direct estimates, under clear sky conditions, when compared with independent reference data.
{"title":"Passive separation of global irradiance into direct normal and diffuse components","authors":"M. Brooks, S. Braden, D. Myers","doi":"10.1117/12.730683","DOIUrl":"https://doi.org/10.1117/12.730683","url":null,"abstract":"Common methods for ground-based measurement of direct normal and diffuse solar irradiance include the simultaneous use of two instruments, usually a pyrheliometer and pyranometer or two pyranometers one of which is fitted with a shading ring. This article describes a passive method of obtaining the direct and diffuse components using a single pyranometer and an innovative shading band containing regularly spaced perforations to allow for alternate shading and exposure of the instrument's sensor as the sun transits the sky. Under clear sky conditions a saw tooth curve is generated that may be reformed into two distinct curves, one each for global and diffuse irradiance. The unknown direct normal values are then readily calculated. The approach potentially offers a cost advantage over dual-instrument and rotating band systems and an accuracy advantage over the single-instrument approach. In conjunction with a reference pyrheliometer under clear sky conditions, the device can be used in shade-unshade calibrations of pyranometers without need of manual operations. Design of the shading band is described and preliminary experimental results are presented. Results show that good accuracy is obtainable, on the order of ± 40 Watts per square meter for global, diffuse and direct estimates, under clear sky conditions, when compared with independent reference data.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"164 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115137536","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}
D. Reyes-Coronado, G. Rodríguez-Gattorno, M. Espinosa-Pesqueira, J. M. Gardner, G. Meyer, G. Oskam
Titanium dioxide nanoparticles have been prepared by solution-phase methods in the three phases that occur naturally, anatase, rutile, and brookite. The amorphous titania starting material was prepared from titanium(IV) iso-propoxide using iso-propanol as solvent and a small quantity of water. The resulting material was treated hydrothermally in an acid digestion vessel at temperatures between 175 °C and 230 °C with different reactants to obtain the three phases or controlled mixtures of two phases. The nanomaterials were characterized by a variety of techniques, including X-ray diffraction, Raman spectroscopy, electron microscopy, dynamic light scattering, and UV-Vis absorbance spectrophotometry. The results illustrate the relation between the properties of the nanoparticles in the colloid, in the powder, and in nanostructured thin films prepared with the materials. A thorough understanding of synthesis methods is essential for the preparation of nanomaterials with tailored structural, morphological, and ultimately, physical properties.
{"title":"Synthesis and characterization of TiO2 nanoparticles: anatase, brookite, and rutile","authors":"D. Reyes-Coronado, G. Rodríguez-Gattorno, M. Espinosa-Pesqueira, J. M. Gardner, G. Meyer, G. Oskam","doi":"10.1117/12.732647","DOIUrl":"https://doi.org/10.1117/12.732647","url":null,"abstract":"Titanium dioxide nanoparticles have been prepared by solution-phase methods in the three phases that occur naturally, anatase, rutile, and brookite. The amorphous titania starting material was prepared from titanium(IV) iso-propoxide using iso-propanol as solvent and a small quantity of water. The resulting material was treated hydrothermally in an acid digestion vessel at temperatures between 175 °C and 230 °C with different reactants to obtain the three phases or controlled mixtures of two phases. The nanomaterials were characterized by a variety of techniques, including X-ray diffraction, Raman spectroscopy, electron microscopy, dynamic light scattering, and UV-Vis absorbance spectrophotometry. The results illustrate the relation between the properties of the nanoparticles in the colloid, in the powder, and in nanostructured thin films prepared with the materials. A thorough understanding of synthesis methods is essential for the preparation of nanomaterials with tailored structural, morphological, and ultimately, physical properties.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126663616","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}
The green microalga Chlamydomonas reinhardtii is proposed to produce hydrogen in a low-cost system using the solar radiation in Yucatan, Mexico. A two-step process is necessary with a closed photobioreactor, in which the algae are firstly growth and then induced for hydrogen generation. Preliminary results are presented in this work with some planning for the future. Different culture broths, temperatures and light intensities were tested for biomass and hydrogen production in laboratory conditions. The first experiments in external conditions with solar radiation and without temperature control have been performed, showing the potential of this technique at larger scales. However, some additional work must be done in order to optimize the culture maintenance, particularly in relation with the temperature control, the light radiation and the carbon dioxide supply, with the idea of keeping an economic production.
{"title":"A solar photobioreactor for the production of biohydrogen from microalgae","authors":"Luis Panti, P. Chavez, D. Robledo, R. Patiño","doi":"10.1117/12.732468","DOIUrl":"https://doi.org/10.1117/12.732468","url":null,"abstract":"The green microalga Chlamydomonas reinhardtii is proposed to produce hydrogen in a low-cost system using the solar radiation in Yucatan, Mexico. A two-step process is necessary with a closed photobioreactor, in which the algae are firstly growth and then induced for hydrogen generation. Preliminary results are presented in this work with some planning for the future. Different culture broths, temperatures and light intensities were tested for biomass and hydrogen production in laboratory conditions. The first experiments in external conditions with solar radiation and without temperature control have been performed, showing the potential of this technique at larger scales. However, some additional work must be done in order to optimize the culture maintenance, particularly in relation with the temperature control, the light radiation and the carbon dioxide supply, with the idea of keeping an economic production.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124719986","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}
The 20th Century was the age of the Petroleum Economy while the 21st Century is certainly the age of the Solar-Hydrogen Economy. The global Solar-Hydrogen Economy that is now emerging follows a different logic. Under this new economic paradigm, new machines and methods are once again being developed while companies are restructuring. The Petroleum Economy will be briefly explored in relation to oil consumption, Hubbert's curve, and oil reserves with emphasis on the "oil crash". Concerns and criticisms about the Hydrogen Economy will be addressed by debunking some of the "hydrogen myths". There are three major driving factors for the establishment of the Solar-Hydrogen Economy, i.e. the environment, the economy with the coming "oil crash", and national security. The New Energy decentralization pathway has developed many progressive features, e.g., reducing the dependence on oil, reducing the air pollution and CO2. The technical and economic aspects of the various Solar-Hydrogen energy options and combinations will be analyzed. A proposed 24-hour/day 200 MWe solar-hydrogen power plant for the U.S. with selected energy options will be discussed. There are fast emerging Solar Hydrogen energy infrastructures in the U.S., Europe, Japan and China. Some of the major infrastructure projects in the transportation and energy sectors will be discussed. The current and projected growth in the Solar-Hydrogen Economy through 2045 will be given.
{"title":"The solar-hydrogen economy: an analysis","authors":"W. D. Reynolds","doi":"10.1117/12.754371","DOIUrl":"https://doi.org/10.1117/12.754371","url":null,"abstract":"The 20th Century was the age of the Petroleum Economy while the 21st Century is certainly the age of the Solar-Hydrogen Economy. The global Solar-Hydrogen Economy that is now emerging follows a different logic. Under this new economic paradigm, new machines and methods are once again being developed while companies are restructuring. The Petroleum Economy will be briefly explored in relation to oil consumption, Hubbert's curve, and oil reserves with emphasis on the \"oil crash\". Concerns and criticisms about the Hydrogen Economy will be addressed by debunking some of the \"hydrogen myths\". There are three major driving factors for the establishment of the Solar-Hydrogen Economy, i.e. the environment, the economy with the coming \"oil crash\", and national security. The New Energy decentralization pathway has developed many progressive features, e.g., reducing the dependence on oil, reducing the air pollution and CO2. The technical and economic aspects of the various Solar-Hydrogen energy options and combinations will be analyzed. A proposed 24-hour/day 200 MWe solar-hydrogen power plant for the U.S. with selected energy options will be discussed. There are fast emerging Solar Hydrogen energy infrastructures in the U.S., Europe, Japan and China. Some of the major infrastructure projects in the transportation and energy sectors will be discussed. The current and projected growth in the Solar-Hydrogen Economy through 2045 will be given.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"C-21 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132757541","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}
Cunping Huang, Bello Illiassou, A. T-Raissi, N. Muradov
Production of hydrogen by water splitting using solar energy is one of the long sought goals of hydrogen economy. Approximately 33% of solar radiation is emitted as high energy photons while the remaining 67% consists of primarily thermal energy. Utilization of both thermal and photonic energies within the solar spectrum is essential for achieving water splitting at high efficiency. At FSEC, we have developed a solar-thermochemical water splitting cycle for the production of hydrogen. In this cycle, the photonic portion of solar irradiance is diverted and used to drive the hydrogen production step, while solar thermal portion drives the oxygen generation step of the cycle. The photocatalytic hydrogen production step of the cycle employs aqueous ammonium sulfite solution that is oxidized to ammonium sulfate in the presence of nanosized photocatalysts. We have developed a technique for the preparation of polymer encapsulated nanosize photocatalysts that show high activity toward oxidation of ammonium sulfite aqueous solution. The use of nano-scale and defect free photocatalysts hinder the recombination of photo-generated electron-hole pairs, thereby increasing solar to hydrogen energy conversion efficiency.
{"title":"Preparation of high efficiency visible light activated Pt/CdS photocatalyst for solar hydrogen production","authors":"Cunping Huang, Bello Illiassou, A. T-Raissi, N. Muradov","doi":"10.1117/12.734026","DOIUrl":"https://doi.org/10.1117/12.734026","url":null,"abstract":"Production of hydrogen by water splitting using solar energy is one of the long sought goals of hydrogen economy. Approximately 33% of solar radiation is emitted as high energy photons while the remaining 67% consists of primarily thermal energy. Utilization of both thermal and photonic energies within the solar spectrum is essential for achieving water splitting at high efficiency. At FSEC, we have developed a solar-thermochemical water splitting cycle for the production of hydrogen. In this cycle, the photonic portion of solar irradiance is diverted and used to drive the hydrogen production step, while solar thermal portion drives the oxygen generation step of the cycle. The photocatalytic hydrogen production step of the cycle employs aqueous ammonium sulfite solution that is oxidized to ammonium sulfate in the presence of nanosized photocatalysts. We have developed a technique for the preparation of polymer encapsulated nanosize photocatalysts that show high activity toward oxidation of ammonium sulfite aqueous solution. The use of nano-scale and defect free photocatalysts hinder the recombination of photo-generated electron-hole pairs, thereby increasing solar to hydrogen energy conversion efficiency.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130970001","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}
A. Parretta, A. Antonini, M. Stefancich, G. Martinelli, M. Armani
The optical characterization of a CPC concentrator is typically performed by using a solar simulator producing a collimated light beam impinging on the input aperture and characterized by a solar divergence (± 0.27°). The optical efficiency is evaluated by measuring the flux collected at the exit aperture of the concentrator, as function of incidence angle of the beam with respect to the optical axis, from which the acceptance angle can be derived. In this paper we present an alternative approach, based on the inverse illumination of the concentrator. In accordance with this method, a Lambertian light source replaces the receiver at the exit aperture, and the light emerging backwards at the input aperture is analyzed in terms of radiant intensity as function of the angular orientation. The method has been applied by using a laser to illuminate a Lambertian diffuser and a CCD to record the irradiance map produced on a screen moved in front of the CPC. Optical simulations show that, when the entire surface of the diffuser is illuminated, the "inverse" method allows to derive, from a single irradiance map, the angle resolved efficiency curve, and the corresponding acceptance angle, at any azimuthal angle. Experimental characterizations performed on CPC-like concentrators confirm these results. It is also shown how the "inverse" method becomes a powerful tool of investigation of the optical properties of the concentrator, when the Lambertian source is spatially modulated inside the exit aperture area.
{"title":"Inverse illumination method for characterization of CPC concentrators","authors":"A. Parretta, A. Antonini, M. Stefancich, G. Martinelli, M. Armani","doi":"10.1117/12.733605","DOIUrl":"https://doi.org/10.1117/12.733605","url":null,"abstract":"The optical characterization of a CPC concentrator is typically performed by using a solar simulator producing a collimated light beam impinging on the input aperture and characterized by a solar divergence (± 0.27°). The optical efficiency is evaluated by measuring the flux collected at the exit aperture of the concentrator, as function of incidence angle of the beam with respect to the optical axis, from which the acceptance angle can be derived. In this paper we present an alternative approach, based on the inverse illumination of the concentrator. In accordance with this method, a Lambertian light source replaces the receiver at the exit aperture, and the light emerging backwards at the input aperture is analyzed in terms of radiant intensity as function of the angular orientation. The method has been applied by using a laser to illuminate a Lambertian diffuser and a CCD to record the irradiance map produced on a screen moved in front of the CPC. Optical simulations show that, when the entire surface of the diffuser is illuminated, the \"inverse\" method allows to derive, from a single irradiance map, the angle resolved efficiency curve, and the corresponding acceptance angle, at any azimuthal angle. Experimental characterizations performed on CPC-like concentrators confirm these results. It is also shown how the \"inverse\" method becomes a powerful tool of investigation of the optical properties of the concentrator, when the Lambertian source is spatially modulated inside the exit aperture area.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133582960","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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