Chemical, electrochemical and photochemical molecular water oxidation catalysts

• Conversion of H2O into H2 and O2 by sunlight could be a solution for energy shortage.
• Water oxidation (WO) is mechanistically complex and thermodynamically uphill.
• During the last five years a wide range of WO catalysts have been reported.
• Main advances in chemical, electrochemical and photochemical WO are described.
• The best examples of photo-electrochemical cells are also included.

Hydrogen release from the splitting of water by simply using sunlight as the only energy source is an old human dream that could finally become a reality. This process involves both the reduction and oxidation of water into hydrogen and oxygen, respectively. While the first process has been fairly overcome, the conversion of water into oxygen has been traditionally the bottleneck process hampering the development of a sustainable hydrogen production based on water splitting. Fortunately, a revolution in this field has occurred during the past decade, since many research groups have been conducting an intense research in this area.Thus, while molecular, well-characterized catalysts able to oxidize water were scarce just five years ago, now a wide range of transition metal based compounds has been reported as active catalysts for this transformation. This review reports the most prominent key advances in the field, covering either examples where the catalysis is triggered chemically, electrochemically or photochemically.

Figure optionsDownload as PowerPoint slide