Alleviating our dependence on fossil fuels will prove to be a major technological hurdle for the United States in the upcoming decades. Excessive CO2听emissions are having a profound effect upon global warming, and fossil fuels are rapidly diminishing. In order to alleviate our dependence on fossil fuels, and decrease CO2听emissions, it is imperative that alternative energy sources, such as hydrogen and bio-fuels, be utilized. Hydrogen is a particularly promising candidate because it can be produced from water, an essentially inexhaustible resource. In addition, hydrogen is a clean, sustainable energy carrier. Its only byproduct after combustion is water.
Concentrated solar energy, an alternative to fossil fuels, has proven to be capable of providing sufficient energy for producing hydrogen via the splitting of water. However, there are problems associated with this technique, as direct water splitting requires extremely high temperatures (2500 K) and a separation of an explosive mixture of hydrogen and oxygen. Solar thermochemical cycles, avert these obstacles by producing hydrogen and oxygen in separate steps at significantly lower temperatures than 2500 K.