Water photolytic splitting

The photolytic splitting of water into hydrogen and oxygen gas is an environmentally benign and cost effective potential fuel source. 

In another approach, semiconductor materials and devices which are stable in aqueous environment are taken to apply sunlight for direct water splitting. The conversion efficiency, however, is still insignificant, since only a very small portion of the solar spectrum is used. Photolytic response, however, could be shifted into the visible region using chomophores called sensitizers [73]. Research is focusing on the development of transparent and highly active catalysts and techniques of surface modification to increase lifetime and efficiency of PEC devices. 

In the discussions of these approaches below, schematics of representative device configurations are included, accompanied by the basic device band structures to indicate the energetic driving forces behind the photolytic water splitting. Some examples of implementation in laboratory-scale prototypes are also presented. 

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