April 20, 2009 Scientists at the Singapore-based Institute of Bioengineering and Nanotechnology (IBN) have made an unprecedented breakthrough in transforming carbon dioxide, a common greenhouse gas, into methanol, a widely used form of industrial feedstock and clean-burning biofuel. Using "organocatalysts", researchers activated carbon dioxide in a mild and non-toxic process to produce the more useful chemical compound.

The "hot paper" report, published recently in the international chemistry journal Angewandte Chemie, has been described by reviewers as "very important", an classification only given to 10% of the journal's manuscripts.

This is because carbon dioxide emissions remain a hotly debated global issue, and are widely blamed for causing irreversible climate change. Carbon dioxide emissions produced by human activity are predominately due to the consumption of fossil fuels and, although figures vary, its concentration in the earth’s atmosphere are estimated to have risen by more than 30% since the industrial revolution. The Intergovernmental Panel on Climate Change (IPCC) estimates that a 60% reduction of global carbon dioxide emissions is needed if carbon dioxide concentrations are to stabilize at present-day levels.

At the IBN, scientists have been able to make carbon dioxide react with a stable organocatalyst called N-heterocyclic carbene (NHC) under mild conditions in dry air. “NHCs have shown tremendous potential for activating and fixing carbon dioxide,"says Siti Nurhanna Riduan, senior lab officer at IBN. "Our work can contribute towards transforming excess carbon dioxide in the environment into useful products, such as methanol.”

A combination of silica and hydrogen – called hydrosilane – is added to the NHC-activated carbon dioxide, which is transformed into methanol through hydrolysis. "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," explains Dr Yugen Zhang, IBN team leader and principal research scientist.

"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.”

Scientific research becomes increasingly important to find solutions that curb global warming. Current research is focusing on green chemistry, which aims to eliminate the use of hazardous substances to prevent environmental pollution. IBN's research aims to make the mass production of methanol more cost-effective, in the process reducing the amount of carbon dioxide released in the earth's atmosphere.

“We are innovating effective methods of generating clean energy using green chemistry and nanotechnology," explains Professor Jackie Y. Ying, IBN executive director of the Institute of Bioengineering 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.”

Anne Hanrahan