Designing materials for solar water splitting

Efficient solar water splitting has been described as the "holy grail" of a renewable energy economy, as it can directly convert daytime sunlight into a chemical fuel, H₂, which can be stored, transported, and utilized at any time. Integrated synthetic, characterization, and theoretical efforts are being pursued to understand and then design improved oxide and oxynitride semiconductors for this process. This investigation has resulted in the addition of a number of materials to the short list of oxide semiconductors capable of absorbing visible light (Eg < 3.0 eV) while still maintaining a conduction band with a sufficiently high band edge energy to permit H2 production. Progress in the synthesis of oxynitrides for water splitting will also be discussed.