Construction of core–shell FeS2@ZnIn2S4 hollow hierarchical structure S-scheme heterojunction for boosted photothermal-assisted photocatalytic H2 production

Abstract

Photothermal effect materials play an essential role in the field of solar energy utilization, and can provide additional capacity supply during photocatalytic reactions. Herein, the core–shell FeS2@ZnIn2S4 S-scheme heterojunction with coating the ZnIn2S4 nanosheets on the FeS2 raspberry-like hollow spheres was fabricated for photothermal-assisted photocatalytic H2 production. In this catalyst design system, the hollow spherical FeS2 was employed as a photothermal substrate to endow more energy for the ZnIn2S4 photo-generated charge carriers to accelerate the charge migration and elevate the temperature of the reaction system, and the interface charge transfer of the S-scheme mechanism realizes the spatial separation of the charge carriers. Meanwhile, the ZnIn2S4 nanosheet coating coated on the surface of the FeS2 hollow sphere effectively prevented the heat loss of the hybrid system. Under simulated solar irradiation (AM 1.5G), the optimal H2 production rate of the FS@ZIS heterojunction is as high as 5.05 mmol/g/h in the absence of Pt as the co-catalyst (AQE of 13.4 % at 420 nm), which is 47.9 and 53.7 times higher than that of pristine ZnIn2S4 and FeS2, respectively. Furthermore, the hydrogen production tests in simulated seawater demonstrate the extensive environmental adaptability of the as-prepared FS@ZIS S-scheme heterojunction. Our work provides a feasible strategy to construct an S-scheme heterojunction system with photothermal assistance for efficient utilization and conversion of solar energy.