Construction of Fe(III) doping modified AgI/NH2-MIL-68(In/Fe) Z-scheme heterojunction photocatalysts through unique internal and interfacial charge transmission and separation efficiency

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/NH2-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 NH2-MIL-68In, NH2-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.