Hydrogen cyclic water cleavage

Cyclic Water Cleavage — Hydrogen and Oxygen Production via Electron Transfer Catalysis 523... 

Redox potentials for various different Feu/Fem couples are shown in Table 3 and although [Fe(OH)2] is thermodynamically capable of reducing water to hydrogen and does so at elevated temperatures,39 the rate of the reaction is low. It can, however, be increased by the addition of suitable catalysts, eg. Ni salts,39,40 excess [FeSOJ,40 metals such as Ni,40 Cu,40 Pd,18,41 or colloidal Pt.40 Nevertheless, cyclic water cleavage based on this system is unlikely since [Fe(OH)3] is a. highly stable material. 

The majority of studies have led to the photochemical production of hydrogen or oxygen at the expense of a sacrificial electron donor or acceptor, but some systems for cyclic water cleavage have been reported. 

Examination of the various half reactions for hydrogen and oxygen production described in Sections 61.5.4.2-61.5.4.5 suggests that some of these might be coupled to give cyclic water cleavage. 

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