By Jatin Khanna
Researchers at Lehigh University are working on a potentially revolutionary technology in renewable energy known as quantum dots. These "dots" are actually nanoparticles that can absorb electrons of varying energies according to their size, and professors Steve McIntosh and Bryan Berger are developing a novel method to produce quantum dots that is much less energy-intensive and environmentally hazardous than previous ways. They use the energy harnessed by these dots to react carbon dioxide, water, and air to produce methanol. Methanol is a potential biofuel that has a wide variety of applications in the energy industry.
The two professors have received a grant from the National Science Foundation's Emerging Frontiers in Research and Innovation division for the purpose of exploring this novel process. Using the award of $2 million, their group will produce quantum dots using a unique bacterial reaction. QDs are traditionally very expensive to produce, and require using toxic chemicals and precious metal catalysts. The bacterial process used by the researchers is much less energy intensive and therefore, much more environmentally friendly. This is why this research is so exciting. Using these organically produced QDs, they will use the energy in sunlight to generate electricity to reaction carbon dioxide and water to produce the biofuel methanol.
Should it prove fruitful, their research has some very exciting advantages and outcomes. Firstly, the fuels used are very abundant. While not strictly renewable in the same sense as solar and wind energy, there is certainly enough air, CO2, and salt water around to spare. It is certainly a cleaner energy source than fossil fuels, and less wasteful than biofuels. Secondly, the photon efficiency of quantum dots is higher than any other process for making biofuels, and it is even higher than that of solar cells. This is due to the inherent property in quantum dots that one electron is produced for every photon that strikes them, giving a one-to-one ratio of electrons produced per photon. Solar cells will never reach this efficiency because they can only accept photons of certain energies based on the material they are composed of. Certain thermodynamic and quantum effects also prevent solar cells from having such a high efficiency. Quantum dots, on the other hand, can be engineered to accept photons of all energies. Even photosynthesis is not as efficient as this process, since it requires for plant-life to internally process carbon dioxide and water to produce glucose and oxygen.
There are many applications for the methanol produced from this sustainable reaction. For example, companies have already determined a method to convert methanol into ethanol, a commonly used fuel for vehicles. In addition, it could also be used to convert waste or salt water into a viable fuel. Another important potential application for the quantum dots is to convert CO2 released from fossil fuel power plants into methanol. This would be a win-win, since it would prevent CO2 from entering the atmosphere while simultaneously creating a renewable fuel. Last, and this is a bit far-fetched, but in the future the process could serve as a liquid fuel generation process for trips to Mars, and even beyond. The technology is still far from commercial, but it is definitely an exciting breakthrough that could play an important role in transitioning to a low-carbon, cleaner world.