Many photocatalyst materials for water splitting have been developed, particularly since the second half of the 1990s. Highly efficient water splitting on tantalate photocatalysts under UV irradiation has been achieved. Moreover, band engineering by doping, valence band formation, and synthesis of solid solutions, has led to the development of a large number of visible light-driven photocatalysts for H(2) or O(2) evolution from aqueous solutions containing electron donors or acceptors. Z-scheme photocatalyst systems for water splitting to H2 and O(2) under visible light irradiation have been developed. This progress in the development of visible light-driven photocatalysts for water splitting is reviewed. (c) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.