Overall water splitting to form hydrogen and oxygen on a heterogeneous photocatalyst using solar energy is an attractive
process for large-scale hydrogen production. In recent years, numerous attempts have been made for the development of
visible-light-responsive photocatalysts to efficiently utilize solar energy. In this article, recent research progress in the
development of visible-light-driven photocatalysts is described, specifically focusing on our efforts made on the
development of (oxy)nitride photocatalysts for overall water splitting.