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

Abstract

A facile aqueous co-precipitation method is successfully introduced to synthesize ZnS–In₂S₃ solid solution (labeled In_2xZn_3(1−x)S₃, x = 0–1) and Cu²⁺ doped In_1.4Zn_0.9S₃ (x = 0.7) solid solution (labeled Cu(y)/In_1.4Zn_0.9S₃, 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 μmol h⁻¹ for Cu(1%)/In_1.4Zn_0.9S₃ solid solution, in comparison with 79 μmol h⁻¹ for un-doped In_1.4Zn_0.9S₃ 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 In_2xZn_3(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.