SUNLIGHT TO GENERATE SUPER-GREEN FUEL

In continuation with the previous article, in a breathtaking invention by the four chemists at the University of Rochester, hydrogen, which is considered to be the environmental friendly fuel in future, is thought to be produced from water using sunlight. It is also considered to be an alternative fuel source and that’s why people are trying to synthesize hydrogen through various means. In past researchers have devised many ways to produce this future fuel, but not in an environmental friendly way. This time around, they have successfully solved this problem.

"People have used sunlight to derive hydrogen from water before, but the trick is making the whole process efficient enough to be useful", commented Kara Bren, professor in the Department of Chemistry.

Bren and the rest of the Rochester team—Professor of Chemistry Richard Eisenberg, and Associate Professors of Chemistry Todd Krauss, and Patrick Holland—will be working on artificial photosynthesis, which uses sunlight to carry out chemical processes much as plants do. But people have also tried out this process; what makes the Rochester approach different from previous attempts to use sunlight to produce hydrogen from water, is that the device they are preparing is divided into three steps. Each step can be modulated, manipulated and optimized according to our need far more easily than other methods.

FIRST STEP

It uses visible light to create free electrons. A complex natural molecule called a chromophore that plants use to absorb sunlight will be re-engineered to efficiently generate reducing electrons.

SECOND STEP

In the next stage a membrane will be suffused with carbon nanotubes to act as molecular wires so small that they are only one-millionth the thickness of a human hair. To prevent the chromophores from re-absorbing the electrons, the nanotube membrane channels take the electrons away from the chromophores and push toward the third section.

THIRD STEP

In the third module, catalysts put the electrons to work forming hydrogen from water. The hydrogen can then be used in fuel cells in cars, homes, or power plants of the future.

By separating the first and third modules with the nanotube membrane, the chemists hope to isolate the process of gathering sunlight from the process of generating hydrogen. This isolation will allow the team to maximize the system's light-harvesting abilities without altering its hydrogen-generation abilities, and vice versa. Bren says this is a distinct advantage over other systems that have integrated designs because in those designs a change that enhances one trait may degrade another unpredictably and unacceptably.