QDs Help Make Solar Fuel a Reality

A solar-nano device is being created with the hope that it can harness the energy of the sun and convert it into a clean fuel alternative.

Using quantum dots grafted with catalyst molecules, scientists are harvesting the sun’s energy to drive the formation of synthetic fuels in a process known as artificial photosynthesis.

Members of the consortium at the University of East Anglia (UEA) have already found a way to produce hydrogen from water. A revolutionary future use of this technology could be to make the fuel for hydrogen-powered cars, rather than making it from fossil fuel.

Luminescence from solutions of small semiconductor clusters (quantum dots) of different sizes. By simply changing the size of the dots, the researchers can change the color of light they absorb or give out – so they can match the dots to the part of the solar spectrum they want to collect. (Image: Nanoco Technologies Ltd.)

Now the scientists are aiming to use the same technology to create alternatives for other fuels and feedstock chemicals, including turning methane into liquid methanol and carbon dioxide into carbon monoxide.

The sun’s potential is vast – just one hour of sunlight is equivalent to the amount of energy used over the world in an entire year – yet no one has yet tapped into its immense power to make fuels.

“To make better use of the fantastic resource we have in our sun, we need to find out how to create solar fuel that can be stored and shipped to where it is needed and used on demand,” said Wendy Flavell, a professor at the University of Manchester who also worked with UEA and the Universities of York and Nottingham on the research. “Most hydrogen so far is obtained from fossil fuels, which are of course, not going to last forever, so it is important to get energy from renewable sources. This is a first step in taking the vast power of the sun and using it to provide the world’s fuel needs.”

At the Royal Society’s annual Summer Science Exhibition held July 5 to 10, Flavell and her team will be displaying an interactive world map that will show children and other visitors just how much energy the sun provides.

There also will be a chance to see the quantum dots at work and to show how – simply by changing the size of the dots – the color of light they absorb or give out can be changed.

A solar cell that produces hydrogen directly from the electricity generated also will be on display, and there will be a chance to race solar-powered and hydrogen-powered model racing cars.

“Creating catalytic devices which harvest light energy using quantum dots, or photovoltaic materials, to drive the formation of synthetic fuels from water or carbon dioxide can be viewed as artificial photosynthesis,” said Chris Pickett, professor at the University of East Anglia. “Globally, chemists, physicists and materials scientists are coming together to work on artificial photosynthesis to get to a stage where we can viably make clean, green fuels.”

For more information, visit: www.manchester.ac.uk