The development of efficient ways to exploit the energy from the sun is an issue of major importance. Among possible solutions, the employment of solar energy to promote chemical reactions has the advantage of addressing the problems of harvesting, converting and storing energy at the same time. In this context, water splitting plays a central role both for direct hydrogen production and for the production of hydrocarbons. Therefore, great attention has been recently devoted to hydrogen production by means of photoelectrochemical (PEC) cells, via water splitting to molecular hydrogen and oxygen. The main challenge is to develop anode materials for these cells that can split water efficiently.