Photocatalytic Hydrogen from Water Over Semiconductors

Water splitting to produce hydrogen (H2) over a semiconductor photocatalyst using solar energy is a promising process for the large-scale production of clean chemical energy in the form of H2, a clean and renewable energy carrier. Many efforts have been implemented to discover photocatalysts that workable under visible-light irradiation to efficiently utilize solar energy. Generally, a suitable cocatalyst to provide an active redox site, is a recognize manner to modify the water-splitting photocatalysts. Apart from that, the constructed two-step photoexcitation photocatalysts, mimicking the natural photosynthesis system, using two different semiconductor powder, have many merits, including amplified light harvesting, spatially separated reductive and oxidative active sites, and perfectly preserved powerful redox ability, which advantage the photocatalytic performance. Especially, a photocatalytic framework called Z-scheme, which is fundamentally comprises of a H2-photocatalyst and an O2-photocatalyst to perform water reduction and oxidation, individually. This chapter describe the fundamental development of water-splitting photocatalytic systems.