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

The rectification effect of the Schottky barrier (at the interface of CdIn 2 S 4 /CNFs) in the CdIn 2 S 4 /CNFs/Co 4 S 3 tandem heterojunction restrained the reflowing of photo-induced electrons from CNFs to CdIn 2 S 4 . Besides, the beneficial built-in electric field (at the interface of CNFs/Co 4 S 3 ) can improve the electron-transfer rate for boosting hydrogen production. More importantly, the ISI-XPS measurement was facilely performed to confirm the dynamic behavior of charge carriers in the ternary composite. • A CdIn 2 S 4 /CNFs/Co 4 S 3 Schottky heterojunction is designed for hydrogen generation. • The rectification effect of Schottky heterojunctions is originally utilized. • The photoelectricity results verify effectiveness of this strategy. • The UPS result reveals the suited band structure and internal electric field. • The electron transfer path was directly verified via the ISI-XPS method. The efficient charge separation and adequate active sites are crucial factors for hydrogen (H 2 ) evolution from solar-driven water splitting. Herein, a novel one-dimensional-two-dimensional (1D-2D) CdIn 2 S 4 /carbon nanofibers (CNFs)/Co 4 S 3 tandem Schottky heterojunction was synthesized by in-situ electrospinning combined with a hydrothermal method. The CNFs with in-situ embedded Co 4 S 3 nano-grains provided an excellent 1D substrate with plentiful active sites, which benefited the growth of 2D ultrathin CdIn 2 S 4 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 H 2 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.