Amorphous Ti(iv)-modified flower-like ZnIn2S4 microspheres with enhanced hydrogen evolution photocatalytic activity and simultaneous wastewater purification

Abstract

In this work, a series of Ti(IV)/ZnIn₂S₄ composite photocatalysts were demonstrated by a facile two-step method. A Ti(IV) component was introduced into the flower-like ZnIn₂S₄ microspheres, which could act as an effective hole co-catalyst, shorten the charge migration distance, provide abundant active sites, inhibit the recombination of electron–hole pairs and mitigate the photocorrosion effect of ZnIn₂S₄. Benefiting from these favorable properties, the amorphous Ti(IV) modified ZnIn₂S₄ showed excellent H₂ evolution performance which can reach 3685.2 μmol g⁻¹ h⁻¹, higher than that of pure ZnIn₂S₄ (2335.5 μmo g⁻¹ h⁻¹). Meanwhile, the modified ZnIn₂S₄ exhibits good stability after several consecutive hydrogen production runs. The photocatalytic purification of methyl orange (MO) in simulated wastewater was further tested. The degradation efficiencies, TOC removal, and highest hydrogen production were respectively 95%, 28.8% and 2650 μmol g⁻¹ h⁻¹. These results may provide an inspiration for tailoring multifunctional semiconductors with amorphous metal ions, which can be used as a photocatalytic H₂ evolution catalyst with high-efficiency, as well as purifying the wastewater simultaneously.