Scientists at Singapore's Institute of Bioengineering and Nanotechnology (IBN) have succeeded in unlocking the potential of carbon dioxide - a common greenhouse gas - by converting it into a more useful product.
In the international chemistry journal Angewandte Chemie, the IBN researchers report that by using organocatalysts, they activated carbon dioxide in a mild and non-toxic process to produce methanol, a widely used industrial feedstock and clean-burning biofuel.
Organocatalysts are catalysts that are comprised of non-metallic elements found in organic compounds. NHCs such as IMes (1,3-bis-(2,4,6 trimethylphenyl)imidazolylidene) are a form of organocatalysts that are stable and easily stored. They do not contain toxic heavy metals and can be produced easily without high costs.
The scientists made carbon dioxide react by using N-heterocyclic carbenes (NHCs), a novel organocatalyst. In contrast to heavy metal catalysts that contain toxic and unstable components, NHCs are stable, even in the presence of oxygen. Hence, the reaction with NHCs and carbon dioxide can take place under mild conditions in dry air.
The IBN scientists showed that only a small amount of NHC is required to induce carbon dioxide activity in a reaction. "NHCs have shown tremendous potential for activating and fixing carbon dioxide. Our work can contribute towards transforming excess carbon dioxide in the environment into useful products such as methanol," said Siti Nurhanna Riduan, IBN Senior Lab Officer, who is also pursuing her Ph.D. under the Scientific Staff Development Award at IBN, one of the research institutes of Singapore's A*STAR (Agency for Science, Technology and Research).
Hydrosilane, a combination of silica and hydrogen, is added to the NHC-activated carbon dioxide, and the product of this reaction is transformed into methanol by adding water through hydrolysis.
Yugen Zhang, Ph.D., IBN Team Leader and Principal Research Scientist, explained, "Hydrosilane provides hydrogen, which bonds with carbon dioxide in a reduction reaction. This carbon dioxide reduction is efficiently catalyzed by NHCs even at room temperature. Methanol can be easily obtained from the product of the carbon dioxide reaction. Our previous research on NHCs has demonstrated their multiple applications as powerful antioxidants to fight degenerative diseases, and as effective catalysts to transform sugars into an alternative energy source. We have now shown that NHCs can also be applied successfully to the conversion of carbon dioxide into methanol, helping to unleash the potential of this highly abundant gas."
Previous attempts to reduce carbon dioxide to more useful products have required more energy input and a much longer reaction time. They also require transition metal catalysts, which are both unstable in oxygen and expensive. Ongoing research at IBN aims to find cheap alternatives for the hydrosilane reagent so that the production of methanol can be even more cost-effective for mass industrial production.
"At IBN, we are innovating effective methods of generating clean energy using green chemistry and nanotechnology. In the face of environmental pollution, global warming and increasing demands on diminishing fossil fuel resources, we hope to provide a viable alternative energy option for industry, and effective sequestration and conversion of carbon dioxide," said IBN Executive Director. Jackie Y. Ying, Ph.D.
The research was published online in the Angewandte Chemie International Edition, at this link: 10.1002/anie.200806058. IBN's report has been designated a "Hot Paper." In addition, the findings have been determined by reviewers to be "very important" - a recognition provided to less than 10% of the journal's manuscripts.
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The Institute of Bioengineering and Nanotechnology (IBN) was established in 2003 and is spearheaded by its Executive Director, Jackie Yi Ru Ying, Ph.D., who has been on the Massachusetts Institute of Technology's chemical engineering faculty since 1992, and was among the youngest to be promoted to professor. In 2008, Dr. Ying was recognized as one of "One Hundred Engineers of the Modern Era" by the American Institute of Chemical Engineers for her groundbreaking work on nanostructured systems, nanoporous materials and host matrices for quantum dots and wires. Under her direction, IBN conducts research at the cutting-edge of bioengineering and nanotechnology. Its programs are geared towards linking multiple disciplines across all fields in engineering, science and medicine to produce research breakthroughs that will improve healthcare and our quality of life.
IBN's research activities are focused in the following areas:
- Drug and Gene Delivery, where the controlled release of therapeutics involve the use of functionalized polymers, hydrogels and biologics for targeting diseased cells and organs, and for responding to specific biological stimuli.
- Cell and Tissue Engineering, where biomimicking materials, stem cell technology, microfluidic systems and bioimaging tools are combined to develop novel approaches to regenerative medicine and artificial organs.
- Biosensors and Biodevices, which involve nanotechnology and microfabricated platforms for high-throughput biomarkers screening, automated biologics synthesis, and rapid disease diagnosis.
- Pharmaceuticals Synthesis and Nanobiotechnology, which encompasses the efficient catalytic synthesis of chiral pharmaceuticals, and new nanocomposite materials for sustainable technology and alternative energy generation.
IBN's innovative research is aimed at creating new knowledge and intellectual properties in the emerging fields of bioengineering and nanotechnology to attract top-notch researchers and business partners to Singapore . Since 2003, IBN researchers have produced a total of 490 papers published/in press, of which 223 were published in journals with impact factor greater than 3. IBN also plays an active role in technology transfer and spinning off companies, linking the research institute and industrial partners to other global institutions. As of March 2009, IBN has filed 692 patent applications on its inventions and the Institute is currently looking for partners for collaboration and commercialization of its portfolio of technologies. IBN's current staff strength stands at around 170 scientists, engineers and doctors. With its multinational and multidisciplinary research staff, the institute is geared towards generating new biomaterials, devices, systems, equipment and processes to boost Singapore 's economy in the fast-growing biomedical sector.
IBN is also committed to nurturing young minds, and the institute acts as a training ground for PhD students and undergraduates. In October 2003, IBN initiated a Youth Research Program to open its doors to university students, as well as students and teachers from various secondary schools and junior colleges. It has since reached out to more than 28,900 students and teachers from 201 local and overseas schools and institutions.