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Solar–hydrogen Energy Cycle
Solar–hydrogen energy cycle is an energy cycle where a solar powered electrolyzer is used to convert water to hydrogen and oxygen. Hydrogen and oxygen produced thus are stored to be used by a fuel cell to produce electricity when no sunlight is available. Working Photovoltaic panels convert sunlight to electricity. In this cycle, the excess electricity produced after consumption by devices connected to the system, is used to power an electrolyzer. The electrolyzer converts water into hydrogen and oxygen, which is stored. This hydrogen is used up by a fuel cell to produce electricity, which can power the devices when sunlight is unavailable. Features The Solar–Hydrogen energy cycle can be incorporated using organic thin film solar cells and microcrystalline silicon thin film solar cells This cycle can also be incorporated using photoelectrochemical solar cells. These solar have been incorporated since 1972 for hydrogen production and is capable of directly converting sunlight ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Energy
Solar energy is radiant light and heat from the Sun that is harnessed using a range of technologies such as solar power to generate electricity, solar thermal energy (including solar water heating), and solar architecture. It is an essential source of renewable energy, and its technologies are broadly characterized as either passive solar or active solar depending on how they capture and distribute solar energy or convert it into solar power. Active solar techniques include the use of photovoltaic systems, concentrated solar power, and solar water heating to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light-dispersing properties, and designing spaces that naturally circulate air. The large magnitude of solar energy available makes it a highly appealing source of electricity. In 2020 solar energy has been the cheapest source of Electricity. In Saudi Arabia a power purchase agreemen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoelectrochemical Cell
A "photoelectrochemical cell" is one of two distinct classes of device. The first produces electrical energy similarly to a dye-sensitized photovoltaic cell, which meets the standard definition of a photovoltaic cell. The second is a photoelectrolytic cell, that is, a device which uses light incident on a photosensitizer, semiconductor, or aqueous metal immersed in an electrolytic solution to directly cause a chemical reaction, for example to produce hydrogen via the electrolysis of water. Both types of device are varieties of solar cell, in that a photoelectrochemical cell's function is to use the photoelectric effect (or, very similarly, the photovoltaic effect) to convert electromagnetic radiation (typically sunlight) either directly into electrical power, or into something which can itself be easily used to produce electrical power (hydrogen, for example, can be burned to create electrical power, see photohydrogen). Two principles The standard photovoltaic effect, as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power To Gas
Power-to-gas (often abbreviated P2G) is a technology that uses electric power to produce a gaseous fuel. When using surplus power from wind generation, the concept is sometimes called windgas. Most P2G systems use electrolysis to produce hydrogen. The hydrogen can be used directly, or further steps (known as two-stage P2G systems) may convert the hydrogen into syngas, methane, or LPG. Single-stage P2G systems to produce methane also exist, such as reversible solid oxide cell (rSOC) technology. The gas may be used as chemical feedstock, or converted back into electricity using conventional generators such as gas turbines. Power-to-gas allows energy from electricity to be stored and transported in the form of compressed gas, often using existing infrastructure for long-term transport and storage of natural gas. P2G is often considered the most promising technology for seasonal renewable energy storage. Energy storage and transport Power-to-gas systems may be deployed as adjunct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photocatalytic Water Splitting
Photocatalytic water splitting is an artificial photosynthesis process using photocatalysis for the dissociation of water (H2O) into hydrogen () and oxygen (). Only light energy (photons), water, and a catalyst(s) are needed, since this is what naturally occurs in natural photosynthetic oxygen production and CO2 fixation. Hydrogen fuel production using water and light (photocatalytic water splitting), instead of petroleum, is an important renewable energy strategy. Concepts 2 mol is split into 1 mol and 2 mol using light in the process shown below. : \begin\\ \ce\\ \end The process of water-splitting is a highly endothermic process (Δ''H'' > 0). Water splitting occurs naturally in photosynthesis when the energy of four photons is absorbed and converted into chemical energy through a complex biochemical pathway (Dolai's or Kok's S-state diagrams). O–H bond homolysis in water requires energy of 6.5 - 6.9 eV (UV photon). Infrared light has sufficient energy to mediat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoelectrolysis Of Water
Photoelectrolysis of water, also known as photoelectrochemical water splitting, occurs in a photoelectrochemical cell when light is used as the energy source for the electrolysis of water, producing dihydrogen which can be used as a fuel. This process is one route to a "hydrogen economy", in which hydrogen fuel is produced efficiently and inexpensively from natural sources without using fossil fuels. In contrast, steam reforming usually or always uses a fossil fuel to obtain hydrogen. Photoelectrolysis is sometimes known colloquially as the ''hydrogen holy grail'' for its potential to yield a viable alternative to petroleum as a source of energy; such an energy source would supposedly come without the sociopolitically undesirable effects of extracting and using petroleum. Some researchers have practiced photoelectrolysis by means of a nanoscale process. Nanoscale photoelectrolysis of water could someday reach greater efficiency than that of "traditional" photoelectrolysis. Semicon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Energy Storage
Energy storage is the capture of energy produced at one time for use at a later time to reduce imbalances between energy demand and energy production. A device that stores energy is generally called an accumulator or battery. Energy comes in multiple forms including radiation, chemical, gravitational potential, electrical potential, electricity, elevated temperature, latent heat and kinetic. Energy storage involves converting energy from forms that are difficult to store to more conveniently or economically storable forms. Some technologies provide short-term energy storage, while others can endure for much longer. Bulk energy storage is currently dominated by hydroelectric dams, both conventional as well as pumped. Grid energy storage is a collection of methods used for energy storage on a large scale within an electrical power grid. Common examples of energy storage are the rechargeable battery, which stores chemical energy readily convertible to electricity to operate a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gibbs Free Energy Change
In thermodynamics, the Gibbs free energy (or Gibbs energy; symbol G) is a thermodynamic potential that can be used to calculate the maximum amount of work that may be performed by a thermodynamically closed system at constant temperature and pressure. It also provides a necessary condition for processes such as chemical reactions that may occur under these conditions. The Gibbs free energy change , measured in joules in SI) is the ''maximum'' amount of non-expansion work that can be extracted from a closed system (one that can exchange heat and work with its surroundings, but not matter) at fixed temperature and pressure. This maximum can be attained only in a completely reversible process. When a system transforms reversibly from an initial state to a final state under these conditions, the decrease in Gibbs free energy equals the work done by the system to its surroundings, minus the work of the pressure forces. The Gibbs energy is the thermodynamic potential that is minim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Iodide
Hydrogen iodide () is a diatomic molecule and hydrogen halide. Aqueous solutions of HI are known as hydroiodic acid or hydriodic acid, a strong acid. Hydrogen iodide and hydroiodic acid are, however, different in that the former is a gas under standard conditions, whereas the other is an aqueous solution of the gas. They are interconvertible. HI is used in organic and inorganic synthesis as one of the primary sources of iodine and as a reducing agent. Properties of hydrogen iodide HI is a colorless gas that reacts with oxygen to give water and iodine. With moist air, HI gives a mist (or fumes) of hydroiodic acid. It is exceptionally soluble in water, giving hydroiodic acid. One liter of water will dissolve 425 liters of HI gas, the most concentrated solution having only four water molecules per molecule of HI. Hydroiodic acid Hydroiodic acid is not pure hydrogen iodide, but a mixture containing it. Commercial "concentrated" hydroiodic acid usually contains 48–57% HI by mass. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aqueous Solution
An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), in water would be represented as . The word ''aqueous'' (which comes from ''aqua'') means pertaining to, related to, similar to, or dissolved in, water. As water is an excellent solvent and is also naturally abundant, it is a ubiquitous solvent in chemistry. Since water is frequently used as the solvent in experiments, the word solution refers to an aqueous solution, unless the solvent is specified. A ''non-aqueous solution'' is a solution in which the solvent is a liquid, but is not water. (See also Solvent and Inorganic nonaqueous solvent.) Characteristics Substances that are ''hydrophobic'' ('water-fearing') do not dissolve well in water, whereas those that are ''hydrophilic'' ('water-friendly') do. An example of a hydrophilic substance is sodium chlo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature Publishing Group
Nature Portfolio (formerly known as Nature Publishing Group and Nature Research) is a division of the international scientific publishing company Springer Nature that publishes academic journals, magazines, online databases, and services in science and medicine. Nature Research's flagship publication is ''Nature'', a weekly multidisciplinary journal first published in 1869. It also publishes the ''Nature-''titled research journals, ''Nature Reviews'' journals (since 2000), society-owned academic journals, and a range of open access journals, including '' Scientific Reports'' and ''Nature Communications''. Springer Nature also publishes ''Scientific American'' in 16 languages, a magazine intended for the general public. In 2013, prior to the merger with Springer and the creation of Springer Nature, Nature Publishing Group's owner, Holtzbrinck Publishing Group, bought a controlling stake in Frontiers. Before Springer Nature was formed in 2015, Nature Research (as the Nature Publi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature (journal)
''Nature'' is a British weekly scientific journal founded and based in London, England. As a multidisciplinary publication, ''Nature'' features peer-reviewed research from a variety of academic disciplines, mainly in science and technology. It has core editorial offices across the United States, continental Europe, and Asia under the international scientific publishing company Springer Nature. ''Nature'' was one of the world's most cited scientific journals by the Science Edition of the 2019 ''Journal Citation Reports'' (with an ascribed impact factor of 42.778), making it one of the world's most-read and most prestigious academic journals. , it claimed an online readership of about three million unique readers per month. Founded in autumn 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander Macmillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the journal; ''Nature'' redoubled its efforts in exp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ScienceDirect
ScienceDirect is a website which provides access to a large bibliographic database of scientific and medical publications of the Dutch publisher Elsevier. It hosts over 18 million pieces of content from more than 4,000 academic journals and 30,000 e-books of this publisher. The access to the full-text requires subscription, while the bibliographic metadata is free to read. ScienceDirect is operated by Elsevier. It was launched in March 1997. Usage The journals are grouped into four main sections: ''Physical Sciences and Engineering'', ''Life Sciences'', ''Health Sciences'', and ''Social Sciences and Humanities''. Article abstracts are freely available, and access to their full texts (in PDF and, for newer publications, also HTML) generally requires a subscription or pay-per-view purchase unless the content is freely available in open access. Subscriptions to the overall offering hosted on ScienceDirect, rather than to specific titles it carries, are usually acquired through a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
