A phenomenon that converts carbon dioxide into organic compounds, particularly sugars, by means of the energy from sunlight is known as Photosynthesis. Photosynthesis takes place in plants, algae, and several species of bacteria. Photosynthetic organisms, since they can make their own food, are known as “photoautotrophs”. Almost all life either depends on photosynthesis directly or indirectly for energy in their food. Photosynthesis is termed form the Greek word “photo” meaning “light”, Synthesis means putting together. In artificial photosynthesis scientists are trying to mimic the natural process of photosynthesis whereby sunlight, water, and carbon dioxide are used to convert into carbohydrates and oxygen. The genuine process that permits half of the entire photosynthetic reaction to occur is “photo-oxidation”. This half-reaction is vital in splitting water molecules as it releases hydrogen and oxygen ions. These ions are required to lessen carbon dioxide into a fuel. The simplest way by which it is potentially possible is with the help of an external catalyst, that can react fast to absorb the sun’s photons. It can solve fuel problems for us by producing inexpensive hydrogen for automotive or jet fuel
Artificial photosynthesis is being pursued to make liquid fuel from carbondioxide and water. Researchers at the Berkeley National Laboratory think this is going to be possible since discovering that nano-sized crystals of cobalt oxide can effectively carry out the critical part of the photosynthetic reaction which is the splitting of water molecules. The photo oxidation of the water molecule to hydrogen ions and oxygen is a an important half reaction in the process of artificial photosynthesis. The electrons released in this part of the reaction is used to reduce carbondioxide to form fuel. Having a catalyst that can effectively capture the photons and utilize them fast enough so as to not waste the sunlight photons is crucial which scientists think the newly discovered cobalt nano crystals are capable of doing. When micron sized cobalt crystals were used the yield was very less but when the scientists replaced it with nanocrystals of cobalt the yield increased by 1600 times which is commensurate with the sunlight flux at ground level. Photosystem II is a process in which manganese-containing enzymes serve as the catalyst for the photo oxidation of water molecules within a complex of proteins. Scientists at he berkeley institute say that the efficiency, speed and size of the cobalt oxide nanocrystal clusters are comparable to Photosystem II. The next step for them to do is have a use this catalytic component to develop a viable integrated solar fuel conversion system.
Although other artificial photosynthesis methods have tried to use the photosynthetic parts of plants, Belcher, the Professor of Materials Science and Engineering and Biological Engineering at MIT and the lead author of the paper in Nature Nanotechnology, Yoon Sung Nam, pursued the method, plants use of having a natural pigment attract the sunlight and then using a catalyst to split the water into hydrogen and oxygen. Thomas Mallouk, the DuPont Professor of Materials Chemistry and Physics at Pennsylvania State University, describes the work as “an extremely clever piece of work that addresses one of the most difficult problems in artificial photosynthesis, namely, the nanoscale organization of the components in order to control electron transfer rates.” The concept behind artificial photosynthesis is to create a method of energy conversion using sunlight. But this preliminary research is a long way from providing an alternative energy source. Belcher believes that within two years, she expects to have a prototype device that can carry out the whole process of splitting water into oxygen and hydrogen, using a self-sustaining and durable system.
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