A team of researchers at the Massachusetts Institute of Technology (MIT) have developed a device to convert sunlight into chemical fuel. The device, which is also called the artificial leaf is made up of silicon, nickel and cobalt.
Artifical leaf
The device does not require any wire connections or circuits and can work in a container with water. When the device is exposed to sunlight, it produces bubbles of oxygen on one side and hydrogen bubbles on the other side. A container that has two sides can effectively segregate and collect the bubbles, which can be stored for later usage.
The device is essentially a sheet of semiconducting silicon, on which a layer of a catalyst made from cobalt is bound. The other side of this sheet is made from an alloy combining zinc, molybdenum and nickel. While the cobalt catalyst releases oxygen, the alloy, which is present on the other side of the sheet releases hydrogen. Without the assistance of wires, the device was able to harvest 2.5% of sunlight energy for hydrogen production. With additional wires and catalysts the device achieved was able to achieve 4.7% efficiency. While it is easy to split hydrogen and oxygen from the water molecules it is difficult to design a collection system, which can separate the two gases. Commercial production on the device has not commenced yet.
According to Daniel Nocera, who is the Professor of Energy and professor of chemistry at MIT, residential homes could use this simple method to create hydrogen and oxygen in separate tanks and then connect the tanks to a fuel cell for generating electricity. Another research is also being done to test the possibility of using cheaper photovoltaic materials such as iron oxide.
Source: http://web.mit.edu