Superb photocatalytic activity of 2D/2D Cl doped g-C3N4 nanodisc/Bi2WO6 nanosheet heterojunction: Exploration of photoinduced carrier migration in S-scheme heterojunction

The intimately-contact 2D/2D heterojunction structure could provide optimal charge transfer/separation interfaces to effectively separate photoinduced charge carriers, thus improving photocatalytic performance. An electrostatic self-assembly technique was applied to construct the 2D/2D Cl doped g-C3N4 nanodisc/ regular rectangular Bi2WO6 nanosheet heterojunction (ClCN/Bi2WO6) in this work. The physicochemical properties of as-prepared samples were systematically characterized by Zeta potential, XRD, FT-IR, SEM, TEM, HR-TEM, XPS, BET, UV-vis DRS, PL, EIS, photocurrent and Mott-Schottky. The maximum photocatalytic hydrogen (H2) generation (421.44 mol g-1 h-1) and photodegradation methyl orange (MO) performance (99%, 40 min) under simulated sunlight irradiation were demonstrated by the 10% ClCN/Bi2WO6, which was 14.1 times and 4.9 times more effective than Bi2WO6. Moreover, the apparent quantum efficiency (AQE) of 10% ClCN/Bi2WO6 is 9.6% at 420 nm. Based on calculations using DFT (density functional theory), the mechanism and driving force of charge transfer and separation of S-scheme heterojunction in this work were investigated and addressed in detail. This study advances the potential evolution of the S-scheme mechanism by offering a unique procedure for the fabrication of 2D/2D heterojunction photocatalysts. (c) 2022 Elsevier B.V. All rights reserved.