Bi2O2CO3–Bi2O2(OH)NO3/g-C3N4 heterojunction as a visible-light-driven photocatalyst with enhanced photogenerated charge separation

Constructing heterojunction to achieve efficient charge separation and transfer is a significant way to enhance photocatalytic activity. Herein, a novel ternary Bi 2 O 2 CO 3 –Bi 2 O 2 (OH)NO 3 /g-C 3 N 4 (labeled as BOC-BON/CN) heterojunction photocatalyst was successfully synthesized by ion exchange reaction under hydrothermal conditions. The products were characterized by various analytical methods, including X-ray diffraction (XRD), Fourier transform-infrared spectrometer (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray spectrometer (SEM), UV–vis reflectance spectra (UV–vis DRS), photoluminescence (PL), photocurrent response and electrochemical impedance spectroscopy (EIS). Heterojunction formation mechanism and photocatalytic degradation mechanism were discussed in detail. The prepared BOC-BON/CN heterojunction exhibited excellent Rhodamine B (RhB) photodegradation rate of 0.0476 min −1 under visible light, which was 3.55 times of the pristine g-C 3 N 4 (0.0134 min −1 ). The significant increase in photodegradation rate was attributable to the heterojunction structure, which promotes the separation of photogenerated charges. Bi 2 O 2 (OH)NO 3 played an essential role as electron accelerator in the charge transfer process. The internal electric field of Bi 2 O 2 (OH)NO 3 accelerates the directed transfer of electron from g-C 3 N 4 to Bi 2 O 2 CO 3 . This work extends the study of g–C 3 N 4 –based photocatalytic systems and demonstrates Bi 2 O 2 (OH)NO 3 as a promising cocatalyst.