Science inches closer to artificial photosynthesis, solar fuels

Scientists are making progress toward developing an “artificial leaf” that mimics a real leaf’s chemical magic with photosynthesis — but instead converts sunlight and water into a liquid fuel such as methanol for cars and trucks.

Energy experts recently discussed such technologies during a symposium aimed at launching a new effort to initiate international cooperation and innovative thinking on the global energy challenge.

The three-day symposium, which took place in Germany this past summer, included 30 chemists from China, Germany, Japan, the UK and the US.

“The sun provides more energy to the Earth in an hour than the world consumes in a year,” states the report — “Powering the World with Sunlight” — released after the symposium. “Compare that single hour to the one million years required for the Earth to accumulate the same amount of energy in the form of fossil fuels. Fossil fuels are not a sustainable resource, and we must break our dependence on them. Solar power is among the most promising alternatives.”

The symposium focused on four main topics:

• Mimicking photosynthesis using synthetic materials such as the “artificial leaf”
• Production and use of biofuels as a form of stored solar energy
• Developing innovative, more efficient solar cells
• Storage and distribution of solar energy

Scientists have already successfully mimicked the fuel-making process used by plants, termed artificial photosynthesis. However, they must now find ways to make that process commercially viable.

Kazunari Domen, a researcher at the University of Tokyo, noted that the ultimate goal of artificial photosynthesis is to produce a liquid fuel, such as methanol, or “wood alcohol.” Achieving this goal would fulfill the vision of creating an “artificial leaf” that not only splits water but uses the reaction products to create a more usable fuel, similar to what leaves do.

Other conclusions of the symposium report include:

• There’s no single best solution to the energy problem. Scientists must seek more affordable, sustainable solutions to the global energy challenge by considering all the options.
• Investing in chemistry is investing in the future. Strong basic research is fundamental to realizing the potential of solar energy and making it affordable for large-scale use.
• Society needs a new generation of “energy scientists” to explore new ways to capture, convert, and store solar energy.

“Building on the success of this first symposium, we’re now gearing up for the future, convening top chemical scientists to address other, equally pressing global challenges,” said Julie Callahan of the American Chemical Society’s office of international activities and principal investigator on the project.