Rational construction of direct Z-scheme SnS/g-C3N4 hybrid photocatalyst for significant enhancement of visible-light photocatalytic activity

Abstract

In this work, a direct Z-scheme SnS/g-C3N4 hybrid photocatalyst was successfully prepared via thermal polymerization followed by in situ chemical deposition method. Morphological observations showed that fine SnS nanoparticles were anchored on the surface of ultra-thin g-C3N4 nanosheets, leading to the formation of tight contact interfaces. The spectral response scope of SnS/g-C3N4 hybrid photocatalyst was widened as compared to that of pure g-C3N4, resulting in the promotion of visible-light harvesting. The photocatalytic efficiency was evaluated through photodegradation of rhodamine B (RhB) upon visible light, and the results showed that SnS/g-C3N4 hybrid photocatalyst exhibited enhanced visible-light photocatalytic performance, which is likely attributed to the synergistic effect of the significantly improved photogenerated electron-hole pairs' separation ability and enhanced light harvesting. The photocatalytic mechanism was examined by employing quenching experiments and electrochemical analysis. In addition, the possible transfer and separation pathway of photogenerated carriers was proposed on the basis of the experimental results. This work will open up a new way for designing and constructing other direct Z-scheme g-C3N4 based photocatalysts.