Constructing a Z-scheme (3-Bi2O3/g-C3N4 heterojunction with enhancing photocatalytic activity for sulfamethoxypyridazine degradation

Despite the potential of Bi2O3 as a photocatalyst for wastewater treatment, its efficacy is undermined by the fast recombination of photo-generated carrier. To address this drawback, we have devised a straightforward impregnation and calcination approach to incorporate (3-Bi2O3 onto g-C3N4, and synthesized a series of (3-Bi2O3/ g-C3N4 composites by coupling (3-Bi2O3 with g-C3N4. Subsequently, the morphologies, chemical structures, optical and photoelectrochemical properties of the obtained photocatalysts were characterized via scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) surface areas, UV-visible diffuse reflectance spectroscopy (UV-vis DRS), transient photocurrent density, Mott-Schottky (MS) and electrochemical impedance spectroscopy (EIS) measurement. The photocatalytic activity of (3-Bi2O3/g-C3N4 composites was evaluated through the degradation of sulfamethoxypyridazine (SMP). The results indicated that the 30%(3-Bi2O3/g-C3N4 photocatalyst (with a (3-Bi2O3/g-C3N4 mass percent ratio of 30 %) exhibited the highest degradation performance, which was primarily attributed to the enhanced migration of photo-generated carriers resulting from the formation of a Zscheme heterojunction between (3-Bi2O3 and g-C3N4. Moreover, the apparent rate constant (k) for SMP degradation employing the 30%(3-Bi2O3/g-C3N4 catalyst was 1.55 and 3.16 times that of pure g-C3N4 and (3-Bi2O3, respectively. Finally, cyclic degradation experiments revealed the excellent reusability of 30%(3-Bi2O3/g-C3N4 for SMP removal.