Band engineering of Cu2+ doped In2xZn3(1-x)S3 solid solution with high photocatalytic activity for H2 production under visible light

A facile aqueous co-precipitation method is successfully introduced to synthesize ZnS-In2S3 solid solution (labeled In2xZn3(1-x)S3, x = 0-1) and Cu2+ doped In1.4Zn0.9S3 (x = 0.7) solid solution (labeled Cu(y)/In1.4Zn0.9S3, y = 0-4%). Their band gap energies are dependent on the compositional x and y values. The photocatalytic hydrogen generation rate can be remarkably improved to 438 mu mol h(-1) for Cu(1%)/In1.4Zn0.9S3 solid solution, in comparison with 79 mu mol h(-1) for un-doped In1.4Zn0.9S3 solid solution. It is suggested that the coupling of the two traditional band engineering strategies of making solid solution and metal ion doping is beneficial to obtain an appropriate conduction band position and effective charge separation of Cu2+ doped In2xZn3(1-x)S3 solid solution, thus improve the photocatalytic activity. This work provides a new opportunity to design novel efficient photocatalysts for water splitting into hydrogen.