Material replicates photosynthesis

New Materials Asia, April, 2007

A group of researchers at Kyoto University, Japan, has developed a nanotechnology material that could be used to replicate the natural process of photosynthesis at a much lower cost than is currently possible.

The innovation could lead to an efficient and relatively cheap system that uses sunlight to synthesize sugars and alcohols from carbon dioxide (C[O.sub.2]) and thereby mop up excess C[O.sub.2] in the atmosphere.

Hideki Koyanaka, an assistant professor at the university, along with other researchers used a unique firing technique to produce pure small particles of manganese dioxides. The micro-particles are only several nanometres in size.

The material is based on manganese, which costs only a few hundred yen per kilogram, and can be produced at a commercially viable cost. The team thinks it could be used to create small, commercially practical devices to cut C[O.sub.2] emissions from sources such as automobiles and power plants.

Scientists have found that manganese plays a central role in photosynthesis. The Kyoto University researchers have increased the total surface area of manganese dioxide particles by reducing their size to a nanoscale. That has made the material more reactive and suitable for mimicking the chemistry of natural photosynthesis. In theory, the material could reduce atmospheric C[O.sub.2] some 300 times more efficiently than plants, the researchers say.

In an experiment using 10 g of the material and weak fluorescent light, C[O.sub.2] was successfully eliminated. Use of sunlight would accelerate the reaction and boost the efficiency of the process, the researchers believe.

Artificial photosynthesis is a vibrant field of research. Some materials have already been developed to use energy from light to convert C[O.sub.2], but these materials are all expensive and unsuitable for commercial use.

For further information, contact: Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan.