A stable Bi2S3 quantum dot–glass nanosystem: size tuneable photocatalytic hydrogen production under solar light

Abstract

The present work comprises a novel approach to design a bismuth sulfide (Bi₂S₃) quantum dot (QD) glass nanocomposite system by confining nano-Bi₂S₃ in a designated glass composition for solar light driven hydrogen (H₂) production. Numerous methods have been reported for the synthesis of Bi₂S₃, however, we have demonstrated the synthesis of Bi₂S₃ QDs (0.5–0.7%) in silicate glass using the melt and quench method. X-ray diffraction and electron diffraction patterns of the glass nanosystem exhibit an orthorhombic crystallite system of the Bi₂S₃ QDs. Transmission electron microscopy demonstrates that 3–5 and 7–10 nm size Bi₂S₃ QDs are distributed homogeneously in a monodispersed form in the glass domain and on the surface with a “partially embedded exposure” configuration. The role of glass on the control of the size and shape of Bi₂S₃ QDs and their effect on the photocatalytic hydrogen generation has been discussed. The maximum H₂ production i.e. 6418.8 μmol h⁻¹ g⁻¹ was achieved for the Bi₂S₃–glass nanosystem under solar light irradiation. This glass nanosystem shows an excellent photostability against photocorrosion and also has a facile catalytic function. Therefore, even a very small amount of Bi₂S₃ QDs is able to photodecompose H₂S and produce hydrogen under visible light. The salient features of this QD glass nanosystem are reusability after simple washing, enhanced stability and remarkable catalytic activity.