1.��School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China;��
2.��Department of Chemistry, School of Sciences, Tianjin University, Tianjin 300072, China
Abstract Hydrogen is a clean energy, and has a heating value three times higher than petroleum. Presently it is mostly produced from fossil fuels (natural gas, oil and coal). However, water��splitting has been regarded as a promising way to produce hydrogen because it is renewable and water is abundant on Earth. Different methods of hydrogen production from water have been, or are being developed, such as electrolysis, photocatalysis, direct thermal decomposition, thermochemical processes and so on. Production of hydrogen by water electrolysis is a mature technology. The key problem of this method is how to reduce its cost. The performance of photocatalysis has been studied extensively both in theory and in practice. As a result, the activity of catalyst is very important for this method. Few reports on direct thermal decomposition have been presented for its high reaction temperature. Thermochemical hydrogen production is a means of splitting water via a series of chemical reactions and the advantage of this method is efficient and scaleable. However, material problems at the high temperatures have hindered the practical implementation of thermochemical cycles.��
2012, Vol. 29 
