Sulfur-substituted In(OH)(3) [hereafter denoted as In(OH)(y)S-z] and Zn-doped In(OH)(y)S-z [hereafter denoted as In(OH)(y)S-z:Zn] are synthesized in an aqueous Solution of ethylenediamine via the hydrothermal method. The photoactivities of these catalysts for H,) production are investigated in the presence of Na2S and Na2SO3 sacrificial reagent under visible light illumination (lambda > 420 nm). The absorption edge of In(OH)(y)S-z shifted monotonically from 240 nm for In(OH)(3) to 570 nm for In(OH)(y)S-z when the atomic ratio of S/In in the synthesis solution is increased from 0 to 2.0. But the absorption edge of In(OH)(y)S-z:Zn shifted from 570 to 470 nm as the atomic ratio of Zn/In in the synthesis solution was increased from 0 to 1.0. The catalyst In(OH)(y)S-z is active for H-2 production, with an average rate of H-2 of 0.9-1.8 mu mol/h, under visible light illumination. The The rate of H-2 production is 35.8 and 67 mu mol/h on 2wt% Pt-loaded In(OH)(y)S-z:Zn photoactivity of In(OH)(y)S-z is enhanced by doping with Zn2+ catalyst when X = 0.2 and 0.5, respectively, corresponding to a quantum efficiency of 0.32 and 0.59% at 420 +/- 10 nm, respectively. (c) 2005 Elsevier Inc. All rights reserved.