The development of highly efficient strategy to facilitate comprehensive charge transmission and effective spatial charge separation is expected as a promising approach to improve photocatalytic performance. Herein, the Fe(III) doping modified AgI/NH 2 -MIL-68(In/Fe) Z-scheme heterojunction (ANM-x composite) with unique internal and interfacial charge transmission performance was fabricated by a facile ion exchange precipitation method. The optimized ANM-50 composite exhibits the maximum photocatalytic activity for the degradation of tetracycline, which is about 9.54, 2.61 and 1.86 times higher than that of pure NH 2 -MIL-68In, NH 2 -MIL-68(In/Fe) and AgI, respectively. The characterization results displayed that Ag nanoparticles (NPs) were generated during the photocatalytic procedure, which not only served as a charge transfer-highway, but also reduced the charge flow energy barrier, thereby accelerating charge transfer efficiency and consolidating the stability of the Z-scheme heterojunction. Mechanism exploration reflected that the superior photocatalytic performance was associated with synergetic effect among the introduced Fe(III), constructed ANM Z-scheme heterojunction and the generated Ag NPs, which significantly expands visible light response range and promotes more effective internal and interfacial charge separation. This research not only designs an efficient photocatalyst for decomposing tetracycline, but also opens a new perspective for rational developing Z-scheme heterojunction with unique internal and interfacial charge flow steering.
The Fe(III)-doped BiOCl catalyst was successfully prepared via a one-step solution combustion synthesis (SCS), and they were characterized by XRD, FESEM, HRTEM, XPS, PL and DRS analysis. With the doping of Fe(III), the SCS catalysts become finer and more uniform, and show narrowed bandgap, which makes the Fe(III)-BiOCl can be excited to form photogenerated electrons and holes under visible light irritation and improve the photocatalytic performance. Compared with the SCS BiOCl, the FB1-2 sample exhibits doubled surface area (9.62 m 2 /g), narrowed bandgap (1.35 eV) and quadrupling degrading efficiency for Rhodamine B (RhB) (93% at 60 min). In addition, through the capturing of free radicals, the photocatalytic degradation mechanism of RhB was proposed, in which the active substances ∙O 2 − and h + played a leading role in the degradation process. Owing to the novel one-step combustion process and resulting in excellent photocatalytic performance, the Fe(III) doping BiOCl is demonstrated as a prospective catalyst for degrading dye pollutants.
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To improve the efficiency of photocatalytic reactions, it is important to understand how to achieve fast directional migration and separation of photogenerated carriers at the interface. Here, Fe(III)-doped ZnIn 2 S 4 (ZIS)-coated graphene oxide (GO) composite (GZF) was in-situ prepared via the low-temperature water bath method. Ultrathin Fe(III)-doped ZIS nanosheets were uniformly grown upright on the GO surface. The prepared samples were studied via, such as, X-ray diffraction, scanning electron microscopy combined with energy-dispersive spectroscopy, transmission electron microscopy, ultraviolet spectroscopy, N 2 adsorption–desorption measurements, X-ray photoelectron spectroscopy, and electron spin resonance. Compared with ZnIn 2 S 4 (ZIS)-coated graphene oxide (GZ), the GZF exhibit a 2.26-fold increase in the photocatalytic degradation performance of tetracycline hydrochloride (TCH) in simulated sunlight. Through density functional theory calculations, found that Fe(III) doping introduces new energy levels into ZIS, which effectively narrow its bandgap and thus enhance its light absorption efficiency. It was found that h + , ·O 2 − , and 1 O 2 were the major reactive oxygen species involved in the photocatalysis, and the effect of pH on the catalytic degradation of TCH was examined. Electron spin resonance and density functional theory results indicate that Fe(III) acts as an electron trap in the ZIS structure to promote the separation of photogenerated electron-hole pairs, which in turn enhances the photocatalytic efficiency of GZF-25.
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