Enhanced photodegradation activity of methyl orange over Ag2CrO4/SnS2 composites under visible light irradiation

• Novel visible-light-driven Ag2CrO4/SnS2 composites are synthesized.
• Ag2CrO4/SnS2 exhibits higher photocatalytic activity than pure Ag2CrO4 and SnS2.
• Ag2CrO4/SnS2 exhibits excellent stability for the photodegradation of MO.
• The possible photocatalytic mechanism was discussed in detail.

Novel Ag2CrO4/SnS2 composites were prepared by a simple chemical precipitation method and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectroscopy and photoluminescence spectroscopy. The visible light photocatalytic tests showed that the Ag2CrO4/SnS2 composites enhanced photocatalytic activities for the photodegradation of methyl orange (MO) under visible light irradiation (λ > 420 nm), and the optimum rate constant of Ag2CrO4/SnS2 at a weight content of 1.0% Ag2CrO4 for the degradation of MO was 2.2 and 1.5 times larger than that of pure Ag2CrO4 and SnS2, respectively. The improved activity could be attributed to high separation efficiency of photogenerated electrons-hole pairs on the interface of Ag2CrO4 and SnS2, which arised from the synergistic effect between Ag2CrO4 and SnS2. Moreover, the possible photocatalytic mechanism with superoxide radical anions and holes species as the main reactive species in photocatalysis process was proposed on the basis of experimental results.

Figure optionsDownload as PowerPoint slideThe efficient charge transfer at the interface of Ag2CrO4/SnS2 composite due to forming the inner electric field, which effectively promoted the photogenerated electrons-hole pairs separation.