Carnegie Mellon University

photoGregory Rohrer

Materials Science and Engineering

The greatest potential for photochemically active ceramics to benefit society lies in their ability to catalyze the dissociation of water (photolysis) to produce H2 and O2. As a fuel for the future, hydrogen is especially attractive because it has three times the energy density of oil and its combustion does not create dangerous emissions, greenhouse gases, or radioactive byproducts. Therefore, producing a clean burning fuel from sunlight and water will have a broad and profound effect on society. Although the possibility of using sunlight and water as an inexpensive and abundant source of hydrogen seems unreasonably optimistic, it should be emphasized that the fundamental chemistry for the photo-induced dissociation of water on ceramic oxide surfaces is demonstrable and well established. Furthermore, with materials and systems available today, it is feasible (though not economically practical) to derive all of the energy we need from the sun. Thus, the challenge for scientists and engineers is to devise methods to harvest solar energy both efficiently and inexpensively. Our research has the goal of creating inexpensive composite catalyst structures that combine light harvesting, charge separating, and catalytic functions that will make hydrogen synthesis from water and sunlight economically viable.