Several studies have demonstrated the possibility to develop chemical cells inspired by biological models to produce molecular hydrogen, for example: Selvaggi et al. explored the possibility to use energy captured by the PSII, developing for that goal, an organic-inorganic hybrid system replacing the PSII protein complex by microspheres of TiO a photo-inducible compound. In order to get the hydrogen production, the TiO microspheres were covered with hydrogenases extracted from the marine thermophile Pyrococcus furiosus, in that way the energy of the light was captured by the TiO microspheres and used to generate protons and electrons from water with the subsequent production of 29 µmol de H hour.
The obtained results from immobilization of hydrogenases on the surface of electrodes have demonstrated the viability of incorporating these enzymes in electrochemical cells, due to their ability to produce gaseous hydrogen through a redox reaction. (Hallenbeck and Benemann). This opens the possibility of using biomimetic compounds in electrodes to generate hydrogen.
Until the present day several bio-mimetic compounds have been developed: Collman et al. produced ruthenium porphyrins, furthermore of the bio-mimetic compounds published by the research teams of Rauchfuss, Darensbourg and Pickett (in Artero and Fontecave) who developed bio-mimetic compounds of the [Fe] hydrogenase. More recently Manor and Rauchfuss presented a very interesting mimic compound based in the [NiFe] hydrogenase with bidirectional properties, this compound has the characteristic that it carries two borane protected cyanide ligands at the iron atom. Some works about bio-mimetic compounds of hydrogenases are summarized in table 1.
Table 1. Bio-mimetic compounds of hydrogenases
However, obtaining bio-mimetic compounds able to hydrogen production on an industrial scale still is elusive. For that reason, the research of this topic is a hot spot in science which has taken the efforts of researchers around the world. Recently a review of the works done in bio-mimetic compounds was published by Schilter et al.. Showing that some studies have got promising results in bio-mimetic compounds synthesized in laboratory.