In situ electronic redistribution tuning of ZnIn2S4 nanosheets on NiCo2S4 hollow tube for boosted photocatalytic hydrogen evolution

Abstract

To overcome the serious drawbacks of fast charge recombination and the limited visible-light absorption of ZnIn2S4 semiconductor photocatalyst, herein, in situ growth of 2D ZnIn2S4 (ZIS) on the surface of NiCo2S4 (NCS) hollow tubes was designed and prepared through a multistep solvothermal means. The experimental results indicate that the ZIS@NCS composites possess large specific surface area and abundant photocatalytic active center due to the intimate interface contact between ZIS nanosheets and NCS hollow backbones, which are favorable for visible light absorption and the interfacial carrier transfer in photocatalytic reaction process. Density functional theory further proved the above insights. The dynamics of photo-induced electrons were extensively characterized. As a result, the optimal sample of ZIS@NCS-7 exhibited the highest hydrogen evolution rate of 1950 μmol h−1 g−1, which was 6.1 times that of pristine ZIS and much higher than the other photocatalysts under otherwise identical conditions. The apparent quantum efficiency of ZIS@NCS-7 composites reached 9.3% at 420 nm. This work provides a novel standpoint for the design and construction of more efficient photocatalyst with robust light absorption.