Artificial Catalysts for Photosynthesis

Last Friday, we discussed the TAML catalyst and its uses in many different applications. We also spent some time discussing the work and considerations that go into designing a catalyst for a specific purpose. As I was reading a magazine while sitting in the financial aid office, I encountered an article which discussed photosynthesis and how important and energy efficient the process is. Furthermore, it talked about how researchers are trying to find ways to duplicate this process in a laboratory.

During the first step of photosynthesis, known as the light-dependent step, plants use chlorophyll to capture light and break down water into oxygen and hydrogen. Scientists believe that if a way to produce this hydrogen can be duplicated in a laboratory, it will lead to a new, efficient, and “clean” way to generate hydrogen energy.

A researcher at the Department of Energy, Etsuko Fujita, is trying to synthesize an artificial catalyst made from robust transition metal complexes in an attempt to mimic photosynthesis. Her catalysts are designed to absorb solar energy and reduce CO₂ to CO – a crucial step that plants use to convert carbon dioxide and water into carbohydrates and oxygen. Recently, her lab made an astonishing discovery. One carbon dioxide molecule is activated by the involvement of two energetic metal complexes. Without carbon dioxide, the complexes dimerize much more slowly than expected, causing the rate of photosynthesis to decline. In the lab, this means that her catalyst must display similar activity. Her work goes to show that as society becomes more and more environment-sensitive, we should start to look at the environment itself for clues into better techniques we can use to be “green”. “Nature has found a way to do this over eons,” she says, and if scientists can learn new ways to mimic our natural environment to produce cleaner energy, we may be able to take better steps to protect it.