In search for efficient photocatalysts for water splitting under visible light, the effect of cation substitution on a layered perovskite, La 2 Ti 2 O 7 has been studied . Among various types of dopants, only Cr and Fe showed intense absorption in the visible light region (λ>420nm), over which H 2 was produced photocatalytically from water–methanol solution. XPS measurements indicated that the oxidation state of doped Cr and Fe was +3. The band gap energies of Cr and Fe-doped La 2 Ti 2 O 7 were 2.2 and 2.6eV, respectively, and the H 2 evolution rate was a little higher for the Cr-doped catalyst than that for the Fe-doped one. The theoretical calculation of electronic band structure revealed that the contribution of these dopants on the overall band structure of La 2 Ti 2 O 7 was negligible, but that they formed a partially filled 3d band in the band gap of La 2 Ti 2 O 7 , from which photoelectrons are excited to the conduction band upon visible light absorption.