Category Archives: Nano Technology

Graphene | Graphene Technology | Graphene The Material Of The Future | Graphene Review | Graphene Properties | Graphene Production

       01-graphene-a ultra thin material-graphene extraction from graphite-tracing graphene from graphite-graphite_pencil The graphene is a substance which has a single-layer crystal lattice of carbon atoms, which is unusual since it is different from all of the materials of its kind. Several researchers have identified a way of making this substance, which allows them to use it in various fields and especially for the high-speed electronic devices.

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Graphene Definition:

Graphene is defined as a one atom thin sheet of carbon atoms arranged in a Hexagonal format or a flat monolayer of carbon atoms that are tightly packed into a 2D honeycomb lattice.

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History:

In October 2010, two University of Manchester (U.K.) scientists, Andre Geim and Konstantin Novolselov, were awarded the 2010 Nobel Prize in physics for their research on graphene. Graphene is a one-atom-thick sheet of carbon whose strength, flexibility, and electrical conductivity have opened up new horizons for high-energy particle physics research and electronic, optical, and energy applications.

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Graphene properties:

Graphene oxide, a single-atomic-layered material made by reacting graphite powders with strong oxidizing agents, has the ability to easily convert into graphene a low-cost carbon-based transparent and flexible electronics.

Graphene Oxide:

Graphene oxide has been known in the scientific world for more than a century and was largely described as hydrophilic, or attracted to water. These graphene oxide sheets behave like surfactants, the chemicals in soap and shampoo that make stains disperse in water.

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Mechanical Properties:

Young’s Modulus:

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1. Graphene sheets stack to form graphite with an interplanar spacing of 0.335 nm, which means that a stack of 3 million sheets would be only one millimeter thick.

2. Graphene is a Zero Gap Semiconductor. So it has a high electron mobility at room temperature. It’s a Superconductor. Electron transfer is 100 times faster then Silicon.

3. Graphene has a record breaking strength of 200 times greater than steel, with a tensile strength of 130GPa.

4. Graphene can be used to create circuits that are almost superconducting, potentially speeding electronic components by as much as 1000 times.

5. Graphene electrodes used in lithium-ion batteries could reduce recharge times from two hours to about 10 minutes.

Graphene Production:

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Chemical Vapor Deposition (CVD) and Molecular Beam Epitaxy (MBE) are two other potential routes to Graphene growth.

Applications:

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  • New devices like Touch screens, Micro Displays and Monitors
  • Chip Making, Circuit Designs
  • Solar cells
  • Micro Fuel Cells
  • Air Bag Deployment Systems and Gyroscopes in Car Electronic Stability Control
  • Pressure Sensors, Micro Tips & probes

Artificial Photosynthesis | Artificial Photosynthesis To Create Clean Fuel | Artificial Photosynthesis Solar To Fuel | Artificial Photosynthesis Process

Artificial photosynthesis is one of the newer ways researchers are exploring to capture the energy of sunlight reaching earth.

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Photosynthesis:

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Photosynthesis is the conversion of sunlight, carbon dioxide, and water into usable fuel and it is typically discussed in relation to plants where the fuel is carbohydrates, proteins, and fats. Using only 3 percent of the sunlight that reaches the planet, plants collectively perform massive energy conversions, converting just over 1,100 billion tons of CO2 into food sources for animals every year.

Photovoltaic Technology:

This harnessing of the sun represents a virtually untapped potential for generating energy for human use at a time when efforts to commercialize photovoltaic–cell technology are underway. Using a semiconductor–based system, photovoltaic technology converts sunlight to electricity, but in an expensive and somewhat inefficient manner with notable shortcomings related to energy storage and the dynamics of weather and available sunlight.

Artificial Photosynthesis:

01-photosynthesis system-Artificial Photosynthesis-Artificial Photosynthesis Solar energy to produce hydrogen directly used in fuel cell

Two things occur as plants convert sunlight into energy:

  • Sunlight is harvested using chlorophyll and a collection of proteins and enzymes, and
  • Water molecules are split into hydrogen, electrons, and oxygen.

These electrons and oxygen then turn the CO2 into carbohydrates, after which oxygen is expelled.

Rather than release only oxygen at the end of this reaction, an artificial process designed to produce energy for human use will need to release liquid hydrogen or methanol, which will in turn be used as liquid fuel or channeled into a fuel cell. The processes of producing hydrogen and capturing sunlight are not a problem. The challenge lies in developing a catalyst to split the water molecules and get the electrons that start the chemical process  to produce the hydrogen.

There are a number of promising catalysts available, that, once perfected, could have a profound impact on how we address the energy supply challenge:

  • Manganese directly mimics the biology found in plants.
  • Titanium Dioxide is used in dye-sensitized cell.
  • Cobalt Oxide is very abundant, stable and efficient as a catalyst

Artificial Photosynthesis Operation:

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Under the fuel through artificial photosynthesis scenario, nano tubes embedded within a membrane would act like green leaves, using incident solar radiation (H³) to split water molecules (H2O), freeing up electrons and oxygen (O2) that then react with carbon dioxide (CO2) to produce a fuel, shown here as methanol (CH3OH). The result is a renewable green energy source that also helps scrub the atmosphere of excessive carbon dioxide from the burning of fossil fuels.

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History:

Plants use organic compounds that need to be continuously renewed. Researchers are looking for inorganic compounds that catalyze the needed reactions and are both efficient and widely available.

The research has been significantly boosted by the application of nano technology. It’s a good example of the step wise progress in the scientific world.

Studies earlier in the decade showed that crystals iridium efficiently drove the reduction of CO2, but iridium is extremely rare so technology that required its use would be expensive and could never be used on a large scale.

Cobalt crystals were tried. They worked, and cobalt is widely available, but the original formulations weren’t at all efficient.

Things changed with the introduction of nano technology.

The main point is that this unique approach increasing appears to be feasible. It has the advantage of harnessing solar energy in a form that can be stored and used with greater efficiency than batteries and it is at least carbon neutral.