Photo-assisted H(2) evolution has been realized over the new heterosystem CuFeO(2)/SnO(2) without any noble metal and was studied in connection with some physical parameters. The delafossite CuFeO(2) has been prepared by thermal decomposition from various salts. The polarity of generated voltage is positive indicating that the materials exhibit p-type conductivity whereas the electroneutrality is achieved by oxygen insertion. The plot of the logarithm (conductivity) vs. T (1) gives average activation energy of 0.12 eV. CuFeO(2) is a narrow band gap semiconductor with an optical gap of 1.32 eV. The oxide was characterized photoelectrochemically; its conduction band (-1.09 V(RHE)) is located below that of SnO(2) (-0.86 V(RHE)) at pH similar to 13.5 itself more negative than the H(2)O/H(2) level leading to a thermodynamically favorable H(2) evolution under visible irradiation. The sensitizer CuFeO(2), working as an electron pump, is stable towards photocorrosion by hole consumption reactions involving the reducing agents X(2-) (=S(2)O(3)(2) and SO(3)(2-)). The photoactivity was dependent the precursor and the best performance (0.026 ml h (1) mg(-1)) was obtained in S(2)O(3)(2-) (pH similar to 13.5) over CuFeO(2) synthesized from nitrate with a mass ratio (CuFeO(2)/SnO(2)) equal to unity. A quantum yield of 0.5% was obtained under polychromatic light. H(2) liberation S(2)O(3)(2-) occurs concomitantly with the oxidation of S(2)O(3)(2-) to dithionate and sulfate. The tendency towards saturation, in a closed system, is mainly ascribed to the competitive reduction of the end product S(2)O(6)(2-). (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.