In Situ Template-Free Ion-Exchange Process to Prepare Visible-Light-Active g-C3N4/NiS Hybrid Photocatalysts with Enhanced Hydrogen Evolution Activity

Abstract

Nickel sulfide (NiS) and graphitic carbon nitride (g-C3N4) hybrid photocatalysts were prepared via a simple and reproducible in situ template-free ion-exchange process. The physical and photophysical properties of the g-C3N4/NiS hybrid photocatalysts were characterized by X-ray diffraction (XRD), high-resolution transmission electron microcopy (HRTEM), and ultraviolet visible diffuse reflection spectroscopy (DRS). The photocatalytic hydrogen evolution, photoluminescence spectroscopy (PL), and photoelectrochemical (PEC) experiments indicate that the NiS cocatalysts can efficiently promote the separation of photogenerated charge carriers in g-C3N4 and consequently enhance the H2 evolution activity. The g-C3N4/NiS-1.5 mol % sample shows the highest photocatalytic activity, and the corresponding H2 evolution rate is 44.77 μmol h–1, which approached that of optimal 2.0 wt % Pt/g-C3N4 (47.61 μmol h–1). A possible photocatalytic mechanism of NiS cocatalysts on the improvement of the photocatalytic performance of...