Photoelectrocatalysis for hydrogen production devices

Hydrogen represents one of the most important "green" candidates for the energetic transition toward renewable and sustainable sources. However, hydrogen is mainly obtained from fossil fuel based processes due to the high energy required for its production from water through classical electrochemical methods. Solar driven water splitting, instead, is a sustainable technology which is rapidly reaching efficiencies which make it close to being successfully transferred from laboratory to industry. This chapter reviews the latest trends in the photoelectrocatalytic (PEC) technologies to convert radiant energy into electricity or hydrogen. Basic principles of PEC, main differences with photocatalysis (PC) and direct photovoltaic (PV) approaches, materials used and design of devices and prototypes are hereby discussed. Moreover, a specific section presents the major challenges encountered when scaling up the laboratory scale devices and systems. Finally, trends and outlooks are described.