2D/2D ultra-thin porous carbon nitride/ZnIn2S4 heterojunctions for photocatalytic hydrogen evolution and methyl orange degradation

Abstract

Effective charge separation and sufficiently exposed active sites are both critical limiting factors for solar-driven photocatalytic technology. In this paper, 2D oxygen-doped ultrathin porous g-C₃N₄ (UCN) and 2D ZnIn₂S₄ heterojunctions (UCN-ZIS) are formed by a high-temperature calcination-oil bath method. UCN with a highly ordered 2D heptazine structure within the layers has a suitable energy band structure, while the expansion of the interlayer spacing facilitates the acceleration of electron transfer for the construction of heterojunctions. During the in situ growth process, ZIS is uniformly distributed as ultrathin nanosheets on the high surface area of UCN. The optimised UCN-ZIS photocatalytic degradation of methyl orange reaches 99.4% efficiency (60 min), and the hydrogen precipitation activity reaches 1125.7 μmol g⁻¹ h⁻¹, which is 4.61 times higher than that of pure ZIS, and this heterojunction possesses good photostability. This work contributes to the development of an efficient photocatalytic system with dual functions of hydrogen precipitation and organic pollutant degradation.