2D/2D g-C₃N₄/MnO₂ Nanocomposite as a Direct Z-Scheme Photocatalyst for Enhanced Photocatalytic Activity

Abstract

Constructing two-dimensional (2D) composites using layered materials is considered to be an effective approach to achieve high-efficiency photocatalysts. Herein, a 2D/2D g-C 3 N 4 /MnO 2 heterostructured photocatalyst was synthesized via in situ growth of MnO 2 nanosheets on the surface of g-C 3 N 4 nanolayers using a wet-chemical method. The hybrid nanomaterial was characterized by a range of techniques to study its micromorphology, structure, chemical composition/states, and so on. The g-C 3 N 4 /MnO 2 nanocomposite exhibited greatly improved photocatalytic activities for dye degradation and phenol removal in comparison to the single g-C 3 N 4 or MnO 2 component. On the basis of the electron paramagnetic resonance spectra, X-ray photoelectron spectra, and the Mott–Schottky measurements, we consider that a Z-scheme heterojunction was generated between the g-C 3 N 4 nanosheets and MnO 2 nanosheets, wherein the photoinduced electrons in MnO 2 combined with the holes in g-C 3 N 4, leading to enhanced charge carrier extraction and utilization upon photoexcitation. This work provides an effective approach to construct the 2D/2D heterojunctions for the application in solar-to-fuel conversion and photocatalytic water treatment.