Regulating Electron-transfer over ZnIn2S4 by Sn(II)/Sn(IV) Co-Doping for Efficient Photocatalytic Hydrogen Production.

The development of photocatalysts with efficient charge separation and transferring is essential for efficient photocatalytic H2 generation. Here, we have constructed Sn2+ and Sn4+ double-doped ZnIn2S4 (Sn2+/Sn4+-ZnIn2S4) catalyst by using a one-step solvothermal method. Sn4+ replaces the Zn ion and creates an additional energy state near the Fermi level, which act as electron accepters. The receptor states boost the metallic conductive properties of ZnIn2S4 and reduce the recombination of photo-induced electrons and holes. The Sn2+ combines with edge S atoms of ZnIn2S4 due to the large ionic radius, which modulates the band gap structure. Both experimental results and theoretical calculations show that the Sn2+and Sn4+ ion double doping increases charge density and narrows the bandgap for light capture. Therefore, the Sn2+/Sn4+-ZnIn2S4 catalyst shows an excellent catalytic activity for hydrogen production (2.48 mmol·g−1·h−1), and it is 35.4 times that of the original ZnIn2S4 (0.07 mmol⋅g−1⋅h−1). This work opens a promising path for developing highly efficient photocatalysts for solar photocatalytic H2 generation. [ABSTRACT FROM AUTHOR]