TOPICS

Successfully generated ethanol fuel using solar energy.

Summary

 A research group led by Professor Yutaka Amao (Director of the Research Center for Artificial Photosynthesis, the OCU Advanced Research Institute for Natural Science and Technology, Osaka City University), in collaboration with Mazda Motor Corporation's Technical Research Center, has successfully developed a new artificial photosynthesis technology that can generate ethanol, a low-carbon fuel for automobiles, using solar energy. This research was published online on July 2, 2015 (CEST) in the following academic journal.

 This research will be presented at the 45th Petroleum and Petrochemical Conference, a meeting of the Petroleum Society of Japan, which will be held at Aichi Sky Expo on November 5th and 6th.

Research Background

 The serious issues of global environmental pollution caused by greenhouse gases and other substances resulting from advances in science and technology, the disposal of large amounts of industrial waste, and the depletion of fossil fuels such as oil and coal must be urgently addressed for the sake of future generations.
 In particular, it can be said that it is essential to take action this century to construct low-environmental-impact energy cycle systems and to develop energy conversion systems that effectively utilize greenhouse gases such as carbon dioxide. While it is conceivable to reduce carbon dioxide emissions through regulations, developing methods to actively utilize carbon dioxide as a raw material and convert it into useful substances is also an important issue.
 Under these circumstances, artificial photosynthesis technology, which utilizes solar energy to convert carbon dioxide into new fuels, is attracting much attention. If ethanol, which is attracting attention as a next-generation low-carbon fuel for automobiles and other applications, can be produced, it will become a new application of artificial photosynthesis systems.
 While artificial photosynthesis systems that convert carbon dioxide into methanol, a one-carbon compound, have been reported, technology for producing ethanol, which has one more carbon atom, has not yet been achieved.

Outline of the research

 If we can establish a technology that converts carbon dioxide into methanol or ethanol using solar energy, we can utilize solar energy, a representative renewable energy source, to capture carbon dioxide and convert it into a valuable resource.
 We have been working on constructing a reaction system that produces ethanol using artificial photosynthesis technology with carbon dioxide as the starting material. We devised a method to produce acetic acid from carbon dioxide and methane (or methanol instead of methane) as shown in the figure below, and then synthesized ethanol from acetic acid using artificial photosynthesis technology. As a result of our experiments, we have succeeded in this endeavor.
 To our knowledge, there have been no previous reports of successful artificial photosynthesis technology to synthesize ethanol from acetic acid. Our research has achieved this feat for the first time. In our system, approximately 5% of acetic acid is converted to ethanol when exposed to sunlight for 150 minutes.

Artificial photosynthesis technology for ethanol production using carbon dioxide as a starting material

Expected effect

 Until now, the molecular conversion of carbon dioxide using artificial photosynthesis technology has been limited to products with a carbon number of one, such as carbon monoxide, formic acid, and methanol. If the technology shown in the figure above is achieved, it would enable the production of ethanol, a fuel with greater practical applications, from sunlight and carbon dioxide, potentially providing a new technology on par with conventional bioethanol production from food crops.

Future Developments

 We plan to develop a new artificial photosynthesis technology for producing ethanol fuel from sunlight and carbon dioxide by incorporating the technology of synthesizing acetic acid from methane and carbon dioxide using acetic acid bacteria or similar organisms.

About this research

 This research is a collaborative achievement between our university's Research Center for Artificial Photosynthesis and Mazda Motor Corporation's Technical Research Center.

Publication Information

⇒All Press Release (PDF:256KB)