Photocatalytic Oxidation Of Water By An Inorganic Semiconductor Nanoparticles/Molecular Catalyst Composite System

In the nature of the entire process of photosynthesis, organisms use sunlight to drive a series of energy and electron transfer, to produce oxygen and transfer carbon dioxide into advanced carbohydrates, and to reduce the protons into hydrogen. Inspired by the photosynthesis in nature, the application of this concept into industrial production, the development of attractive new hydrogen production occured. Studies and researches in the biological process foucus on the designning and building a new type of solar energe-chemical molecule conversion system. Based on the principle, artificial photosynthesis is more and more popular in some new feilds. In these researches above, photocatalytic water oxidation reaction produces the protons and electrons for the hydrogen evolution. It is the core to build the artificial photosynthesis system and the most challenging subjects.In this paper, based on the well-known molecular level water oxidation system composed of synthetic molecules catalyst ruthenium photosensitizer, new system including inorganic semiconductor (BiVO4)with photocatalytic activity and molecules cubane structure catalyst Co4O4(O2CMe)4(py)4(py=pyridine, catalyst11) was built. Results show that the new system can achieve O2evolution and is superior in terms of light stability and the efficiency of light utilizition. When the condition is controled in the pH2.4sulfuric acid like that the concertration of the catalyst11is0.5X10-5M, the BiVO4is0.15g and the concertration of the electron acceptor is20mM, the activity of the O2evolution is the best(6hours,64.87μmol totally). And the TON is324based on the concetration of the catalyst. Overcoming short lifetime and easy to decomposing in the past organic molecules photocatalytic water oxidation system. Successfully acheiveing sustainable and efficient light-induced decomposition of water.In the following steps, active species during the reaction has been studied. By changing the subsituents of the pyridine ligand, comparing with the Co-+involved reaction and tracking the changes of NMR and UV spectrum, molecular cubane catalyst can be asserted in the O2evolution.On the other hand, n-type BiVO4photoanode with catalyst11adsorbed on the surface of the semiconductor was examined. The results proved that this kind of molecule-BiVO4photoannde had high photostability and photocurrent.