Metal oxide electrodes for photo-activated water splitting

The present chapter provides a survey of the research results obtained in the past decade in the preparation, characterization, and functional testing of nanostructured metal oxide photoanodes for PEC water splitting applications. After a brief overview of the basic concepts of photoelectrochemical water splitting, the chapter summarizes the most recent and cutting-edge results obtained for photoanode materials based on selected metal oxides. Rather than providing a comprehensive review on the topic, the main goal is to offer a general overview of important achievements in the field, with particular regard to the most effective actions carried out to improve material photoefficiency: (i) tailoring of morphology/ nano-organization; (ii) doping and functionalization with suitable catalysts/activators; and (iii) fabrication of nanocomposites and heterostructured systems. In the discussion of selected experimental results, particular efforts are dedicated to highlighting the interplay between the system features and the ultimate material activity, examined in terms of photocurrent density/potential curves.