HUMANS HAVE been struggling for years to create clean, renewable energy that does not decimate the planet. During plant photosynthesis water and carbon dioxide is turned into glucose and oxygen. Recently, mankind has been trying to learn from plants to produce our own clean, green machines – in this case Artificial leaves.
What are artificial leaves?
“Artificial leaf” is like living leaves; this device can turn the sunlight directly into a chemical fuel that can be stored and used later as an energy source.
Working:
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When artificial leaves are placed in a container of water and exposed to sunlight they quickly begin to generate the streams of bubbles: oxygen bubbles from one side and hydrogen from the other. -
The two streams of bubbles can be collected and stored and used later to deliver power. -
The device is made entirely of earth – abundant, inexpensive materials mostly silicon, cobalt and nickel and works in ordinary water. -
In the past, the highest efficiency achieved in an artificial leaf was 18%, but now the efficiency is increased by 22% which is highest efficiency ever seen in artificial leaves.
Methodology:
To convert the energy of sunlight into chemical energy, the leaf splits water via the photosynthetic process to produce molecular oxygen and hydrogen which is a form of separated protons and electrons. The primary steps of natural photosynthesis involve the absorption of sunlight and its conversion into spatially separated electron-hole pairs. The holes of this wireless current are captured by the oxygen involving complex photosystem to oxidize water oxygen. The electrons and protons produced as a byproduct of the OEC reaction are captured by ferredoxin of photosystem. They are used to produce hydrogen in the form of NADPH. For a synthetic material to realize the solar energy conversion function of the leaf, the light absorbing material must capture a solar photon to generate a wireless current that is harnessed catalyst, which drives the four electrons/hole fuel-forming water splitting reaction under benign conditions.
CONSTRUCTION
The construction of an artificial leaf comprising earth – abundant elements by interfacing a triple junction, amorphous silicon photovoltaic with hydrogen and oxygen. The ability to perform the oxygen evolving reaction in water at neutral condition has several consequences for the construction of the artificial leaf. Electrochemical splitting of water could provide a cheap, clean and renewable source of hydrogen as the altimetry sustainable fuel. If the artificial leaf can be improved to a marketable level, then we could be seeing Forests of them powering our houses, cars and may be even entire cities.
ADVANTAGES
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H2 can be stored and either burned or run through a fuel cell to generate electricity. -
It can store energy in the chemical form that is the great advantage of this device over the panel which we use now a day. -
It is inexpensive as the materials are abundant.
ISSUES
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Safe storing of hydrogen gas. -
Freezing in sub zero temperatures. -
The efficiency needs to be improved. -
For high performance, the cost due to huge silicone solar cell increases. -
If the energy output is too low, then Artificial leaves will never stand a chance at replacing our current sources of energy.
RESEARCH IS UNDERGOING
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To increase the efficiency of this device. -
To explore the use of photovoltaic (solar cell) materials other than silicone such as iron oxide, which may be even cheaper.