Controllable construction of hierarchically CdIn2S4/CNFs/Co4S3 nanofiber networks towards photocatalytic hydrogen evolution

Abstract

The efficient charge separation and adequate active sites are crucial factors for hydrogen (H2) evolution from solar-driven water splitting. Herein, a novel one-dimensional-two-dimensional (1D-2D) CdIn2S4/carbon nanofibers (CNFs)/Co4S3 tandem Schottky heterojunction was synthesized by in-situ electrospinning combined with a hydrothermal method. The CNFs with in-situ embedded Co4S3 nano-grains provided an excellent 1D substrate with plentiful active sites, which benefited the growth of 2D ultrathin CdIn2S4 nanosheets to construct the tandem Schottky heterojunction. It is noteworthy that the spatial charge separation and directional transportation originating from the rectification effect of the Schottky barrier remarkably prolong the charge carrier lifespan. The optimal composite shows the H2 production activity at a rate of 25.87 mmoL·g−1·h−1 and superior photostability. Ultraviolet photoelectron spectra and UV–vis diffuse reflectance spectra revealed the information of the band structure and built-in electric fields in the heterojunction. Moreover, photoelectrochemical measurements and in-situ irradiated X-ray photoelectron spectra verified the efficient carrier separation and electron-transfer path in the heterojunction. This work inaugurates a new avenue in designing the CNFs-based heterojunction for high-efficiency photocatalysis.