Artificial Leaf Offers New Approach to Energy Production

Researchers at the Powering the Planet Center for Chemical Innovation have created an artificial leaf. Just as a natural leaf converts sunlight into water, oxygen and sugar, this stand-alone device captures solar energy and splits water into hydrogen and oxygen gas.

To compete with cheap fossil fuels, novel materials are needed to generate fuels from solar energy. The materials must be inexpensive and abundant and their production simple and low-cost. Through a sustainable distribution infrastructure, the artificial leaf could become a viable energy source for both developed and developing countries.

The artificial leaf converts sunlight into chemical fuel using a silicon photovoltaic cell and relatively inexpensive catalysts-materials that jump-start chemical reactions. The hydrogen catalyst is made from an alloy of nickel, molybdenum and zinc, while the oxygen catalyst is made from the element cobalt. These catalysts enable proton-coupled electron transfer-a process that occurs in nature when plants change water into oxygen.

Like Mother Nature's leaves, the artificial leaf self-assembles, operates in natural water at room temperature and self-heals. When immersed in water in the presence of sunlight, the catalyst-coated silicon wafer produces hydrogen and oxygen bubbles.

This finding was cited by Time magazine as an innovation of the year for 2011.