Metal oxide electrodes for photo-activated water splitting

In order to sustainably meet the future humanity energy needs, alternative energy production techniques, such as artificial photosynthesis, have captured a significant attention. In this regard, the possibility of harvesting sunlight and storing it in chemical bonds for subsequent redistribution is a challenging alternative. In particular, photoactivated water splitting to yield H2, one of the most promising energy carriers, has appealing implications, especially if driven with high efficiency by low-cost and stable inorganic semiconductors. This chapter provides a brief overview on research advancements in photoelectrochemical (PEC) H2O splitting promoted by metal oxides. Specifically, using selected systems as examples, we describe representative works on the improvement of material behavior as photoelectrodes, examining how various performance-limiting issues can be addressed by a fine control of composition, nano-organization and ex-situ treatments. The engineering of suitable systems and their combinations described herein takes significant steps in bringing the target processes closer to reality, paving the way to clean energy generation from renewable sources.