Heterojunction photocatalyst systems are deemed to be an excellent option to improve the photocatalytic behavior of a material. In this paper, Ag2S/SnS2 heterojunction photocatalysts were prepared by a simple in-situ ion exchange method from SnS2 nanosheets. The Ag2S/SnS2 composite photoanode exhibits 13.99 pA/cm(2) photocurrent density at 0.7 V (vs. Ag/AgCl) in 0.5 M Na2SO4 solution and a significant increase in photocatalytic activity compared to SnS2 nanosheets. Ag2S (8 wt%)/SnS2 composite shows the highest activity (0.0440 mg/min) in the degradation of MO and good stability. The reactive species trapping experiments confirmed hole (If-) and hydroxyl radical (center dot OH) are active groups and play key roles in the photocatalytic degradation reaction. The highly effective photoelectrochemical and phocatalytic activities of Ag2S/SnS2 heterojunctions are attributed to the efficient separation of photogenerated hole-electron pairs. This work may provide a novel concept for the rational design of high performance SnS2-based photocatalysts. (C) 2017 Published by Elsevier Inc.