A heterojunction photocatalyst TiO2/AgGaS2 consisting of bulky AgGaS2 with high crystallinity decorated with nanosized TiO2 particles was successfully fabricated by solid state reaction and sol-gel synthesis. TiO2 itself was inactive under visible light, but its combination with AgGaS2 improved greatly the rate of hydrogen production of AgGaS2 from water containing Na2S/Na2SO3 as sacrificial reagents under visible light irradiation. The fabrication method of the heterojunction photocatalysts was critical for their performance. This configuration of photocatalyst results in an efficient charge separation at the interface, followed by fast diffusion of photoelectrons generated in AgGaS2 towards surrounding TiO2 leading to high photocatalytic activity of hydrogen production. (c) 2009 Elsevier B.V. All rights reserved.