Dual functional S-scheme ZnIn2S4/crystalline polymeric carbon nitride (ZIS/CPCN) heterojunction for efficient photocatalytic hydrogen evolution and degradation of levofloxacin

Abstract

Developing dual functional catalysts for photocatalytic hydrogen evolution and pollutant degradation is one of the most ideal methods to address energy and environmental pollution. In the present study, an S-scheme ZnIn2S4/crystalline polymeric carbon nitride (ZIS/CPCN) heterojunction was synthesized using simple hydrothermal and calcination methods. The CPCN with a highly ordered heptazine-imide structure within the layer imparts a suitable band structure, while the widened interlayer spacing facilitates rapid electron transfer through surface engineering to construct heterojunctions. During the in-situ growth process, ZnIn2S4 uniformly distributes on the high surface area of CPCN as ultra-thin nanosheets. Under visible light irradiation, ZIS/CPCN-2 exhibited the highest hydrogen production activity (3492 μmol·g−1·h−1), which was 4 times and 112 times higher than ZIS and CPCN, respectively. Furthermore, the ZIS/CPCN catalyst demonstrated a certain degradation rate for quinolone antibiotics within 180 min, involving the •OH and •O2– radicals, and analyzed the degradation pathway of levofloxacin. The most stable configuration was obtained through theoretical calculations, and the density of states and work function of the sample were computed, proposing the S-scheme mechanism. This work contributes to the development of efficient photocatalytic systems with dual functions of hydrogen evolution and degradation.