7 Apr : In what is hailed as a major scientific breakthrough, scientists have developed a new way to split water from hydrogen and oxygen.A team at Weizmann Institute, led by Professor David Milstein, has demonstrated what it claims is actually a new mode of bond generation between oxygen atoms and even defined the mechanism by which it takes place.
In fact, it is the generation of oxygen gas by the formation of a bond between two oxygen atoms originating from water molecules that proves to be the bottleneck in the water splitting process, a scientific journal reported.
The new approach that the Weizmann team has recently devised is divided into a sequence of reactions, which leads to liberation of hydrogen and oxygen in consecutive thermal – and light-driven steps, mediated by a special metal complex that the scientists designed in previous studies.
Moreover, the one that they designed – a metal complex of the element ruthenium – is a "smart" complex in which the metal centre and the organic part attached to it cooperate in the cleavage of the water molecule.
The team found that upon mixing this complex with water the bonds between the hydrogen and oxygen atoms break, with one hydrogen atom ending up binding to its organic part, while the remaining hydrogen and oxygen atoms (OH group) bind to its metal centre.
This modified version of the complex provides the basis for the next stage of the process – the "heat stage". When the water solution is heated to 100 degrees C, hydrogen gas is released from the complex – a potential source of clean fuel – and another OH group is added to the metal centre.
"But the most interesting part is the third ‘light stage’. When we exposed this third complex to light at room temperature, not only was oxygen gas produced, but the metal complex also reverted back to its original state, which could be recycled for use in further reactions," Prof Milstein said.