科研之友
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摘要
The water oxidising enzyme, photosystem II, performs one of the most important reactions for life on Earth. Today, in the context of finding renewable sources of energy as alternatives for fossil fuels, the four-electron oxidation of water using light energy stands as one of the most challenging reactions for scientists to understand and reproduce. Mastering this reaction is considered to be a key step towards the use of water and sunlight to produce renewable hydrogen. It is therefore not only timely but also urgent to understand the mechanism of this enzyme so that this understanding can be used to design artificial catalysts. A chemical catalyst that shares the property of the enzyme in its ability to oxidize water with a low overpotential, could greatly improve the efficiency of water electrolysis and photolysis. Here we briefly describe aspects of the enzyme focusing on the essential cofactors involved in the light driven oxidation of water and provide an overview of the work done to produce a biomimetic photocatalyst for water oxidation. The development of such a device can be conceptualized as the association of two chemical modules, a photoactive unit and a catalytic unit. The candidate of choice for the photoactive unit, at least on a proof-of-principle basis, is [Ru(bpy)(3)](2+). This is due to its robustness, its synthetic flexibility and its unique photophysical properties. The elusive manganese catalyst acting as the catalytic site is dealt with in the previous chapters of this issue. In this review we discuss the different challenges that must be met to develop a synthetic system for water photolysis. These include (1) efficient light absorption by a sensitizer, (2) development of a stable charge separating device, (3) vectorial electron flow to/from, (3a) a donor site that must be capable to accumulate charges for consequent catalytic reactions, and (3b) an acceptor system that allows a multi-electron process.
- 出版日期2008-2
- 单位中国地震局
