Photocatalytic water splitting using semiconductor particles: History and recent developments

Overall water splitting to produce H₂ and O₂ over a semiconductor photocatalyst using solar energy is a promising process for the large-scale production of clean, recyclable H₂. Numerous attempts have been made to develop photocatalysts that function under visible-light irradiation to efficiently utilize solar energy. In general, overall water splitting over a photocatalyst particle can be achieved by modifying the photocatalyst with a suitable cocatalyst to provide an active redox site. Therefore, the development of active photocatalytic materials has relied on both photocatalysts and cocatalysts. This review article describes the historical development of water-splitting photocatalysts.