Research team pursuing greener production of methanol

Low-cost quantum dots ( QDs) from bacteria to capture energy in sunlight and catalyze

Backed by a $2 million grant from the National Science Foundation, a Lehigh research team is working to create a promising new method of producing renewable fuel.

Using only carbon dioxide, sunlight and water, the Lehigh researchers aim to perfect a low-cost, environmentally friendly process that could enable the production of methanol – which can be used as fuel for cars, heating appliances, electricity generation and more – at commercial scale.

The grant from the NSF’s Division of Emerging Frontiers in Research and Innovation (EFRI) will build on the success of Lehigh’s Faculty Innovation Grant (FIG) and Collaborative Research Opportunity Grant (CORE) programs, which enabled chemical and bioengineering professors Steve McIntosh and Bryan Berger to produce low-cost quantum dots, or QDs, from bacteria.

QDs are small semiconductor particles that were discovered three decades ago. Researchers see their potential in transistors, solar cells, LEDs, lasers, medical imaging and even quantum computing. QDs are also very expensive to make, as they require the use of toxic solvents and costly chemicals at elevated temperatures. Berger’s novel idea to produce QDs from bacteria makes this technology green and affordable.

Through a Lehigh CORE award, McIntosh and Berger worked with Chris Kiely, professor of materials science and engineering and director of Lehigh’s electron microscopy labs, to develop a method of producing QDs at very low cost in bacteria. In their successful EFRI grant, one of only a few awarded nationally last year, they added the expertise of Robert Skibbens, professor of biological sciences, and Ivan Korendovych, assistant professor of chemistry at Syracuse University. Together, the researchers hope that QDs produced through their revolutionary new method can serve as the light-harvesting component of a photocatalyst to efficiently produce methanol fuel.

In their EFRI project, the researchers will couple the QDs with a series of yeast-synthesized enzymes. The QDs will capture the energy in sunlight to generate an energetic electron and electron hole pair. These excited species catalyze the removal of hydrogen from water and carbon from CO2, and produce methanol, a renewable liquid fuel, in a continuous flow process.

The group’s unique biosynthetic process to produce QDs, says McIntosh, enables control of the dots’ particle size and, with that, the wavelength and energy of light captured. It is not only a dramatically less expensive method than using precious metal catalysts, but it also makes large-scale production of liquid fuels far more feasible.

“The biosynthetic QDs not only enable us to design processes to produce liquid fuel at dramatically reduced cost, but also enable the development of an environmentally-friendly, bio-inspired process unlike current approaches that rely on high temperatures, pressures, toxic solvents and precious metal catalysts,” Berger says. “Thus, we are able to develop a unique, ‘green’ approach to liquid fuel synthesis that substantially reduces both cost and environmental impact.”

“In the process of trying to achieve our goals on this project, we also will learn valuable lessons that will advance science in other ways,” says McIntosh. “Making QDs more cheaply and efficiently has many applications, such as efficient lighting, biomedical imaging and displays.

“Currently, there is no commercial route to directly and photocatalytically produce liquid fuels. Certainly, using sunlight to create liquid fuel is a high-risk, high-reward proposition, but that is what is so exciting. The implications for our nation’s economy are significant.”

Tags: CCU

Source: Lehigh University, press release, 2013-08-06.